


Stranger Than Friction

by Auntie_Diluvian, Pyreo



Category: Undertale (Video Game)
Genre: Aspirations of decency, Dry Humping, Eventual Smut, Gender-Neutral Pronouns, Guilt Kink, More Fluff than Smut, Other, Post-Pacifist Route, Reader Is In College, Reader-Insert, Self-Denial, Semi-Public Desk Chair Shenanigans, Slow Build, Teacher-Student Relationship, bed sharing, blanket boners, professor snas, sans pov
Language: English
Status: In-Progress
Published: 2016-04-18
Updated: 2016-07-04
Packaged: 2018-06-03 03:32:33
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 9
Words: 31,123
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6594892
Author URL: https://archiveofourown.org/users/Auntie_Diluvian/pseuds/Auntie_Diluvian, https://archiveofourown.org/users/Pyreo/pseuds/Pyreo
Summary: <blockquote class="userstuff">
              <p>Sans is a busy skeleton nowadays. He's a college professor, and even if he's surprisingly quite good at it, it's a lot of responsibility -- especially when he's not just being judged on the basis of his teaching, but as a makeshift representative of monsterkind. On top of that, he's got grading to do, lectures to plan, physics jokes to test out on his brother, and somehow he even manages to squeeze in the occasional nap. His schedule is full up. </p><p>The last thing he needs is for one of his students to start hitting on him.</p>
            </blockquote>





	1. Potential Energy

**Author's Note:**

> One day, Auntie D said she really wanted there to be a fic where a student crushed on Sans as a college professor. And then ideas came out and writing happened. Eventually so much got written that it pretty much had to get posted, because even though it started out self-indulgent, it ended up self-indulgent and tryhard as hell

Sans is the kind of professor who gets distracted and goes off on a tangent every other class, and eventually someone tells him the hour's up and he warns them that they’re not gonna get him to delay their quiz until the next session again after this. He may not be a loud talker, but his voice is deep enough to cut through any amount of idle chatter and cause a silence. He’s the kind of professor who gets genuinely worried when he notices certain students are skipping class - he understands, honestly. He tries to keep a respectable balance between telling them stories to keep things interesting and having their best interests at heart. They’re not strictly trying to take advantage of him, on the days when he gets distracted, but nobody really wants him to stop, either. 

The period of novelty for him being one of the first monsters in a formal position was, actually, quite short. If anyone was going to adapt to having a skeleton half their height as a tutor, it would be young adults just breaking out of their personal shells. As it turns out, they’re the type of humans Sans gets along with best. They have more important things to worry about than making bone jokes past the first week, and their lives have lost almost all normalcy anyway. How can monsters on campus worry you when you’re typing in the library at 3 am, wrapped in a blanket and eating cereal?

If you asked his students about his style and demeanour, they’d have vaguely positive comments about their first monster tutor. He’s fair, smart, flexible, available, and he’s got a natural, effortless knack for it. Not to mention he has a bit of a rep as the kind of teacher you want to go get drunk with.

"I lied to his face about why I needed an extension, and he gave it to me along with a recipe for a monster hangover cure."

"I've only had him as an advisor for like two years but I shit you not, we have inside jokes."

"Yeah, he went to bat for me when I filed a complaint against Dr. Miller."

"I came in to talk about my capstone and ended up going out for a drink with him just so he could finish his story about his brother."

He’s not tenured. He might never get there. It’s fine. He knows this stuff, he’s good with people. The kids joke around with him. Best job he’s had in years, except for the grading, which he can never seem to keep up with. Still, it works for him. It’s a good fit and it’s worth even the boring parts of the job if it means every day isn’t the same.

There are things he’s not as good at dealing with, however. For all he’s comfortable with the science and the overwhelming majority of his students, he’s not entirely comfortable being in a position of authority. Some of these kids, they call him ‘sir’ and ‘Mr.’ and ‘Dr.’ (even though technically he still doesn’t have a formal degree) and most onerous of all, ‘Professor’, and sometimes he forgets to respond because, oh right, they’re addressing him. He doesn’t think of himself in those terms. But whether or not he’d choose them for himself, they mean something. The titles carry the weight of an obligation.

When it’s business as usual, that weight isn’t such a terrible burden. He’s had worse, much as he’d prefer not to be reminded. But sometimes it’s not business as usual. It never fails to wound him, personally, almost, when a student cheats on a test or winds up crying in his office because they just can’t do it anymore or confides that someone in his own goddamn department is treating them with less respect and decorum than they deserve. Damn convoluted, humans.

He has to be so, so careful.

Cautious, not just to tread a thin line of not making a huge stink as an untenured professor because sometimes his colleagues are just the worst, but also to give off the correct impressions, naturally as the respect for monsterkind will be guided by his actions. It was easy enough, if not extremely bothersome to find clothes that fit the guidelines of the faculty dress code. He sure as hell looks like a professor. But stiff shirts and shoes aside, it’s all too easy to fall on the other side of that line. To forget who he’s supposed to be for these -- well, they’re not kids, are they? Not really. He calls them that but they’re always surprising him with their insight and kindness and resilience and- ha, right. Determination.

There’s one student in particular who’s just brimming with the stuff. They’re in his PHYS 101 class, on the fifth row, usually, towards the middle. A senior, if he remembers right, one of those Humanities majors. He can’t remember them being late a single day (not that he’d know, since he’s usually the last one in the door about 5 minutes overdue) and they’re easily one of his best students in this class. He likes them more than the usual amount. More than what’s strictly professional.

He doesn’t mean to, it’s just he knows a good person when he sees one. They seem like fun, from the way he’s seen them interact with their friends before and after class and the few occasions he’s seen them around campus. They’re so quick, he’s a little jealous of whatever department gets to have them full time because they’re good at this. He likes their laugh, he can pick it out of the small crowd of 50 or so. And they have a nice smile, nice eyes. Whoops.

And as soon as he realises  _ how dangerous  _ this might be for him if it became a problem, he remembers to rein it in. He doesn’t joke back with them. He doesn’t let them goad him into talking, walking with him, anything outside of the classroom. 

It’s maybe equally unprofessional to give a student the brush-off as much as he does with them, but he rationalizes that they’re smart enough, they don’t need his help as much as some of the others do. It’s better to just get them through his class. Better they think him cold and short on pleasantries than making an emotional connection that does not need to be and should not be made. And they probably won’t even notice. Not if he’s careful.

It’s quick and painless. They start making their way from their seat to the table next to the podium after class with a question on their lips and he thinks he’s being tactful when he pretends not to notice their approach and leaves the small lecture hall, legs carrying him out faster than he likes and is used to.

They start missing classes. And when he notices, he’s not sure if it’s concern for a student, or otherwise. Would he have picked up on it as quickly if it were anyone else? They do come to a session now and then. He answers their questions curtly. And then as he leaves the classroom bundled away with a cloud of undergrads who want to try and convince him to demonstrate some magic, he looks back - why did he ever look back - and meets  _ that _ student’s eye as the group leaves them behind. 

It’s not that much of a shock to see them shuffling their feet in the doorframe of his office the next day, timid knock on the open door, all awkwardness and uncertainty. 

“come on in, i just gotta finish up this email right quick. have a seat.”

“That’s okay, I’ll just stand,” they say. Their posture is stiff and they look so uncomfortable, like they’d rather be anywhere else. That’s fine. It only stings a little and it’s better this way. He tries to focus on his email. It’s not actually an important one, but he’s having a hard time concentrating. Whatever they’re about to say, he isn’t going to like it.

Evidently he takes too long and they finally give in and sit in the chair by the bookshelf. Really, the only other chair in there besides his. It's only maybe their second time in his office. The first time was at the start of the semester and it hadn't been clean then, but it's way worse now that classes are in full swing. He had plants on his windowsill, gifts from friends judging by the ribbons tied around the pots, but they're all dead and rotting in the sunlight so the flies are made to choose between the dead amaryllis and the browned apple core in the tupperware container. 

Finally he finishes up and swivels to face them. He nods toward the paper they have stretched between their hands in their lap and they hand it to him. The edges are warped by sweat where they were holding it. It’s a drop form, signed by them and their advisor, dated a week ago.

They’re within their rights. The deadline to drop a class without a penalty isn’t for another week. Still. He had wanted to get them through his class without incident, not see a bright student drop out a third of the way into the semester. Shit.

He takes their paper, clears a spot on his desk, signs it and hands it back to them. He hates how relieved they look.

“ok. well, uhh, you’re free to go-” They start gathering up their things. They’re halfway out of their chair already but he has to know. “-but i gotta ask. i mean, you don’t have to answer if ya don’t want, but why’re you dropping my class all of a sudden?”

They sit back down but their hands ball into fists. They remain silent.

"'cuz i know you've missed class for a few weeks now, and ya don't have to tell me about why that is, but if it's something dumb like the material or whatever, there's other options we can look at. cuz you're really smart, i'm sure you can bounce back from this with a little help."

They fidget with their hands.

“Ah, no. The- the coursework is fine. I don’t really, um, have an excuse for missing classes, and it’s fine. I can just take Chem or, hah. I dunno, Plants and People next semester. It’s fine.”

His eye sockets go wide at “Plants and People.”

“plants and p- oh, jeez, please do not do that.” That earns him a strained chuckle. “ok, so if it’s not the coursework, what is it? you can go at any time, but it’s killin’ me to know i’m gonna lose a student to feel-good fake science.”

They inhale deeply, the gears clearly turning in their head. “It’s the, uh. The learning environment?” they squeak.

He draws a blank. No, maybe he misunderstood. He listens again, in his mind.

“you’re one of those education majors, aren’t you.”

They nod.

“well, i’m not, so you’re gonna have to tell me what that’s code for. i mean, i don’t have control over the auditorium or the class size or anything so. wait, is it. is someone else in the class makin’ you wanna quit?”

Their brows shoot up. “Oh no, no! Well, okay, sort of, but it’s not-”

“who.” 

Shit. Is he supposed to ask that? Is it a conflict of interest? He doesn’t care, the idea that anyone could make someone as bright and promising as this one student want to drop out is one that he can’t abide.

“Uh, well. I’ve sort of felt like,” they begin, eyes scanning the titles on his bookshelf, “I mean, really just on occasion, and maybe I’ve been imagining it.” He’s leaning forward in his seat, staring them down.

“But I get the impression that you don’t want anything to do with me. That you’ve been keeping me at arm’s length? And it wouldn’t be so much of a problem if, if you weren’t so different with everyone else and. I swear I thought I was just being oversensitive until I saw you running out the other day. And I thought, well, why bother if I’m clearly not wanted here?”

He can’t even deny that. That’s the conclusion he wanted them to come to, if it came down to a choice between thinking he’s way too interested in them or totally disinterested. This is his own damn fault. Because he wasn’t careful enough. He braces his hands on his kneecaps and squeezes.

“shit. shit. ok look, i know it probably means jack shit now, but you’re right. this is my fault, but i’m willing to make it up to ya. you have your paper. it's up to you whether or not you hand it in before the deadline, but hear me out first. if you want help catching back up so you don't have to throw away a third of a semester's worth of work, and i dunno why anyone would ever wanna do something more than once if they don't have to, then shoot me an email and we'll set up a time where you can come in and go over some of the key points of the lectures you missed, one on one. again, you're smart, i don't think you'll have a problem learning twice the material in half the time. i don't want an answer right now. but let me know what you decide. or don't. if i never hear from you again i'll know you betrayed me for one of the life sciences and you'll be dead to me anyway."

They glance at their completed paperwork, considering, then back to him. Meeting his eyes, they shove the form down in their bag with no measure of their usual care. He registers the sound of crumpling paper as a triumph. It's a premature one, but he gets the point he hopes they're trying to make. 

They leave. Well, at least now he might have a chance to do his job properly. He considers the whole interaction once or twice, a few times, he keeps dwelling on the way he obviously showed he wanted to get away from them. It was not fair. To either of them. Sometimes he has to put his entire being into the effort of thinking back on the details, and not imagining some new ones.

Maybe it's just him, maybe he can't pretend any more that loneliness isn't a thing he does. Maybe he needs to address that he wants some companionship, and god, why did he have to discover this by thinking about someone he shouldn’t during the insomnia-wracked small hours of the morning.

The personal tutoring session starts off simple enough, they have notes, he has his lecture points. He reminds himself to correct his previous cold shouldering and that he’s allowed to make jokes. He’s allowed to ease out of his fake professional persona. He’d hate himself if a student failed or left because of him. They make a reference to a sitcom he’s only just watched and he victoriously returns fire, which spins off into a battle of human pop culture knowledge in which he’s eager to prove himself. An hour later and it's the evening and "we could pick somewhere else and keep going" and they agree and he knows he's making up for a lot of lost time to pal around because he was right, they're fun, and they end up going to a bar.

As long as he throws in a physics based pun now and then, it still counts. Right?

And it's not that weird, he knows his colleagues go to this bar along with the students, it's a relaxed sort of atmosphere much like how he gets along with people. It's not him he's worried about, it's this kid who's buying themselves drinks faster than he really thinks is necessary. Like hell he could bring that up. 

A group of their friends arrives and surrounds them. He knows some of them, some of them he doesn't, but he sees his opportunity to escape while he still has a clear head, if he  _ ever had _ a clear head. He tries to settle his tab while they're talking about whatever early 20-somethings talk about -- he's not delusional enough to think he knows, anymore -- but the bartender is taking forever and the printer runs out of receipt paper and… Shit, it's too late. They've already waved their friends away by the time he calculates the tip. He tries not to look at them as he signs his name because they're tipsy and transparent and hurt that he was so obviously trying to get away from them at the first opportunity. Again. They tease him about it, badly, betraying their wounded pride with a "Leaving so soon?" that's a parody of nonchalance.

He waves a hand at them in a vague, dismissive gesture. "yeah, i gotta get home, pretend i'm gonna grade some exams…”

This poor excuse is followed by polite, stilted arguing. But they're stubborn and yes, Determined. He agrees to wait for them to pay and catch up. Outside, at his very own maddening suggestion. Why the fuck's he waiting for them outside? He should have waited inside where there were other people around,  _ witnesses _ , if waiting for them at all was a  _ thing _ they were going to insist on. Just what does he think is going to happen? What do  _ they _ think is going to happen? He's such a prize idiot, this is nothing but trouble and bad news all the way down.

They join him outside, shivering despite the drunken flush on their cheeks. They stand in silence for a moment too long for him to be comfortable. They clear their throat and ask, with as much clarity as they can muster, if it's not too much of an imp… impo.  imp-sos-ition could he walk them home because it’s a ten minute walk and it's dark and they’re kind of drunk and they feel like the buddy system is highly underrated?

He can't say no to that, because that would make him feel like an asshole. 

And he doesn't see any harm in the request, anyway. It's him with the problem. Besides, they have a point and they're safer with him than they know. In some ways, more than others. So he walks them home without incident, aside from a few stops to tie a shoe, pet a stray cat, or marvel at how fast the clouds are traveling, until their apartment comes into view. He's not gonna walk them the rest of the way to their door, that's overkill, that's date territory. 

He disengages with as much tact as he can muster. They smile, turn to him and thank him for everything. For giving them the extra help and for his company. And that should be it, there’s nothing left, all possible appropriate words have been exhausted, but they're stuck there on the sidewalk, looking at him, staring almost, color rising on their face.

They lean ever so slightly and he flinches, clears his throat and gives them a cheesy grin and a salute. He stumbles back a couple of paces.

"no problemo, pal."

And he turns tail and leaves, practically shaking. He already knows he's going to be revisiting this situation a thousand times over in his head and pondering all the disastrous ways this could have gone.

If they end up not coming back to his class, if he’s managed to make this too intense, then he’s failed. But there's a gap of half a week before the next class, and anything awkward does fade away during the interval. He has to look nonchalant when scanning the rows - not like he's looking for them - and to not look surprised when they're there near the back. And funnily enough, it gives him some confidence. Is it that they didn’t reject the idea of finishing the semester with him? Is it a validation more close to home? He refuses to answer.

He really tries his best. He’s gonna set things out properly, talk about particles and minute forces and battling gravities without being distracted, and he actually gets lost in it and overruns. By the time he ushers the bulk of his students away and waves while he collects his notes and everyone files out, he's legitimately not really thinking about personal problems any more.

Until he looks up again and  _ they _ are standing in front of him and he nearly drops his papers.

"Hey. I'm glad I didn't drop out, I'm pretty sure. You sure know how to make this stuff interesting. So... thanks."

It's just what he should have done. It's fine. He’s pleased with himself and he’s not staring, he’s just looking at them to note their appreciative expression.

"Also, thanks for the other night, that was fun. And making sure I got back okay and everything. Uhh. I just think more guys should be like you."

They leave quickly, and after they’re gone he slowly leans his head onto the desk and stays there.


	2. Schrödinger's Moral Grey Area

**Notes for the Chapter:**

> We hope you enjoy this even half as much as we did writing it!

Why is this happening to him. Why would a young adult, with all the new opportunities for connections in a university, be looking twice at someone who has to tape glasses to the sides of his head?

It rattles around in his skull for a few hours. Days. 'More guys should be like him'. Are humans - or humans of that age - just that bad in comparison with him, because he tried to be understanding and decent? He didn’t have an overly high opinion of humans when he and his friends and Frisk emerged from Underground, and although it improved both before and after taking the teaching job, it’s been up and down. Whatever this student thought about him could be chalked up to sheer curiosity on their part. And on his. He wasn’t that curious. Nope. Since when had _that_ led to anything good?

Their next make-up session (and if he's smart about it, their last) arrives and he's forced to identify the heavy, twitchy feeling accompanying it as dread. There's something else there, too, most definitely _not_ dread but that gets shoved down even deeper. He doesn't need that, he needs to focus on cramming as much of Unit 2 into their brain as possible so he can wash his hands of this whole mess.

Unfortunately, they aren't cooperating with his vision of finality for this session. They struggle the entire way through and he's concentrating so hard on giving the exact correct impression, keeping this all business without being cold to them, that he almost misses why they're struggling.

He keeps a steady eye on them and watches the furrow of their brow while they think. It's not that they don't understand the concepts or that they don't know how to work through this kind of problem, it's that they don't seem to trust their own instincts. He watches them almost write down the correct answer, then erase it and take two more unnecessary steps. They look at him sheepishly, and he fights the urge to appreciate that.

"That's not right and I know it," they say, laughing, and he can't help laughing with them. He gets up and erases the last two steps, then resumes his perch on the edge of his desk.

"you almost had it. here. you're killin' me, why'd you change it?" They have nothing to offer but a shrug. He shrugs back, mocking them or maybe himself. "look, you-- you've got good instincts, you seem to understand more than you think you do, you've just gotta trust that you know what you're doin', here."

Their back is to him, but their head tilts a few degrees and he can just barely see their tongue peek out from between their lips. They write the correct answer on the board, larger than the rest of the equation, and circle it before turning to face him. They got the right answer, which begs the question of why they still look like they’re puzzling out an equation.

They just look at him and he realizes what he's just implied. He didn't mean that. This wasn’t. Honestly he was just trying to teach, not encourage them to make a move. He jolts back in tearing his eyes away too quickly.

The plastic of the marker cap squeaks as they replace it. They bite their lip and set it down in the tray. The tension has ratcheted up so suddenly, it's suffocating. They cross the small space to where he's sitting on his desk. His office, in spite of all his cluttered mess, has never felt as tiny as it does right now.

They're not looking at him, their eyes are trained on the weird patterns in the old carpet, but he can see their face is bright red. He can't breathe. Their hand comes to rest just above his knee, pressing in the loose fabric around the bone. If he were somehow watching from above, detached from the situation, he'd be laughing at the clumsy come-on. But he's not. He finds his voice, by some miracle.

"what are you doing."

"I'm trusting my instincts."

"'sreally not what i meant by that."

His words stick together more than usual.

"I know what I'm doing."

His eyes are closed. He needs to collect himself. But he can't do that when they're touching him, coming on to him. He needs a fucking moment and it's a damn good thing their hand stays put.

He gets himself together and hops down from the desk, slips by them and fixates on cleaning the whiteboard. He even uses the little spray bottle of cleaner he's never touched before.

"so unless you have other questions, i guess i'll see you in class tomorrow." his voice gives everything away but please, god, could they just pretend with him? They gather their things and go, pausing at the door like they want to say something else, but then think better of it.

He's glad they're gone, but he knows what determination looks like and it's written all over them when he catches a glimpse of them out the window.

The only thing keeping him company in bed after that is cold, aloof integrity. He's proud of it. But he thinks about being in his tiny office with them, too, and he replays the touch of their hand on his leg, and needing space more than anything in the world. It's not like it's a crime to think about it. To give himself empty, heartless praises over and over for doing the right thing. Great going, Sans. You didn’t do a bad.

It's still not something that plagues him with sexual urges, it's not as base as all that. But after that entirely too close call, he does end up idly... _lazily_ touching himself when he reconsiders their actions. Not touching like how humans do it. More just imitating what they might do. Poking around his body, testing the solidity of it. The stuff he'd want somebody to explore about him. Mirroring the ways he wants to explore them too. Humans are absolutely nothing if not fascinating.

In his classes he mostly goes through practice papers now, which is more boring, and his--... _they_ haven't asked him anything, talked to him, they've just shown up to every session and taken notes. Fine. And then they leave quickly at the end. Fine. He doesn't know what he'd expect them to come up and say. He’s relieved that they don’t.

There’s other things going on in his life to keep his mind occupied, anyway. There's an event coming up, a fancy kind of shindig. (Sans really wants to make a joke out of ' _shin_ dig' but so far nobody's asked him about the event...) It's an opening of a new hall for classes concerning monsterkind and monster history. Added on thanks to a grant, and it's a big deal, news outlets and everything. It's basically assumed he's going to be there. He's not really wondering if _they're_ coming, too. Uh, much.

It's open for everyone, including students, to look at the new supplies and equipment and details about the new courses. He realises he has to find a suit that fits him and there follows one of the more uncomfortable afternoons of his life, and only perseveres because Papyrus forces him to. His brother already owns a suit (two, actually) and is eager to accompany him, to see this little corner of Sans’s world. It comforts him greatly to know he won’t be going alone.

The main university hall is decked out with banners and balloons. More casual than the dress code would indicate, especially with student and staff milling around and chatting casually. Papyrus goes missing in the crowd nearly instantly, as Sans knew he would do, with his excited voice audible from anywhere in the room. The evening starts out with a speech and a few words from the directors and a monster representative, the works. He watches the students hanging back, keeping to themselves in the shyer groups. It’s a good idea to include them, they respond well to responsibilities. They're actually interested in this stuff. Hell, seeing bunches of humans earnestly getting involved in monster-human integration is a great perk of the job. It leaves him hopeful for the future, for once.

It's easy to get swept up in all the glamour and academia for a while, chatting among the faculty. He gets brought down to earth again with a bump when he spots a face a little too well etched in his memory from across the room, surrounded, predictably, by their friends. He turns away as fast as possible.

The conversation around him filters out because oh, god. They’re all dressed up, and so elegantly, and here he is in a modified tux that's _still_ hanging weirdly around his shoulders, and it's hard enough to stay in conversations with the other tutors when they're twice his height. When he comes back to his senses there's a wall of faces looking at him for whatever answer they were all anticipating from him, and he's sweating now. He asks them to repeat it, he was miles away.

A couple of minutes later there's a tug on his arm.

"Ex-- excus--- I'm sorry, could I talk to you for a minute? Dr., uhm... Sans?"

He can't just blow that off without looking like an asshole in front of everyone. His brain overworks trying to find non-suspicious words to use as he agrees and--

Suddenly he's away from the group, he's following them around a corner, he doesn't even question where they're going, because he's busy staring at what they're wearing and how nice the colour is and how nicely it fits on them--

A door closes behind them. They're in one of the new accessible rooms, more suited for monster variety. It's a cool space, it's a hopeful sort of educational gesture. He's thinking about _that_ because he can't bear to look at them.

"I just wanted to say... I'm sorry? Um..." He looks over so fast his neck clicks. Fuck. They really look smart. They seem aloof, not facing him, studying some of the educational materials like he was. "I thought you... well, we both... I mean, I shouldn't have done it anyway..."

He releases a breath too hard and it whistles between his teeth.

"kid."

"Hey, don't worry," they chuckle, nervously. "I'm not gonna try and kiss you, I swear." He unclenches his fists, almost relieved until his mind comes to terms with the gravity of those words being said out loud. "Sorry, it's just. I think-- I really thought you were cool, and all. And I thought you... okay, never mind."

Sans isn't sure what they're babbling about because he thought everything before was pretty clear. An apology is nice, but he doesn’t want it to turn into something like last time. Still, even assuming they're being sincere, what could he possibly say to that? They're right, after all. Didn't they hold all the cards? After last time, with him barely holding it together, he thought they had him pretty much found out. Not to mention the sudden change in heart. Their apology made him more comfortable, but he'd still be a fool to let his guard down completely.

"it's, ah, i mean. no worries. we're good.”

"You've been really helpful, y'know, and... after I was gonna drop out." They look more assured. Bubbly, even. They pat him, leaving their hand on his shoulder. "It was nice. I... I'm not gonna do anything. I just..."

He could try not to panic. He doesn't know what's going on anymore.

"I just really thought I was reading some of your signals right. And, um. If I'm _not_ wrong, then I just want you to know that there are still, umm. Options on the table. Or if I am wrong, but you change your mind? I’ll still be here."

He's dumbstruck. They bend down, trying to get him to look them in the eyes but he just stares off over their shoulder.

"Look," they say, sounding about a thousand times less sure of themselves, as this was clearly not the reaction they were hoping for, "Just. You're very attractive and I really do like you and. I'm new at this, okay?"

That finally draws a response from him. "god, i'd _hope_ so. and i hope you stay new, cuz kid, what the fuck do you think is gonna happen?" He thinks this is what heartburn must feel like. He's not sure if he's angry or horny or overjoyed or just tired of this.

He’s clearly not giving off the signals that would encourage someone to continue, and his language is firmly on that side of the issue too. But this is one of those determined humans, and how does he always end up with these ones?

“I’m not going to do anything. Nothing that will get you in trouble. Honestly,” and he does sneak a look at them, which turns out to be a mistake. They’re so close to him now. Stooping down to get a better look at him while they talk, their eyes meet his, and he sees the kind of hope in there he could never dare to have in a million years.

They shuffle. Their arms loop around him and he’s clasped to them and both their expensive clothes are crinkling and being incredibly loud in contact with each other. He feels their nose on his cheek and the gentle, _gentle_ sensation of their chin, their hair. It’s not even a nuzzle, it’s softer than that.

“I’m not kissing you,” they murmur, voice warm and deep. “I’m not, I swear, I’m not… doing anything wrong, I just…” their lips graze him as they speak and he’s shuddering, helplessly, what has he done to cause this. What has he _done_.

His cell phone buzzes noisily against his keys in his pocket and at the same time he jumps, as their arms tighten around him before turning him loose. They're flushed and drawing shaky breaths, and he doesn't want to know what he looks like. It's a text from Papyrus, wondering where he'd run off to hide. He replies fast. His fingers don't work right and half the words are misspelled but he gets the point across.

"'smy brother. gotta go. i'll...." he's not in any kind of position to be making promises - to himself, to them, to whatever deity happens to be paying attention - so he trails off and leaves, bumping the doorframe on his way back to the hall, leaving them in the dark classroom.

He stops in the hallway. Why did he stop? This is so awkward. Papyrus already knows he’s on his way back. He turns. Re-opens the door.

He was going to go back just to say something that would make this less of a burden to deal with later. But he doesn’t say anything. He can’t bring himself to condone it. He doesn’t need to, because in a second he’s back in their arms with his eyes clenched shut and his breaths are hitching.

He doesn’t say a thing, but his arms are around their waist now and he’s trying to stop shaking.

“Oh my god,” they tell him, as their eyes wander all over his diminutive form and hold him tight and one hand cups the back of his clammy skull. “Oh my god.” They sound so excited, in wonder of a discovery. He only wishes he shared the feeling. “You’re gorgeous.”

He pulls away slower this time and is more deliberate about his departure. He’s ashamed, but there are no other sounds to taint the sweet savouring of those last words. He shuts the door silently and traverses the corridor with his hands in his pockets.

He spends the rest of the evening in a bit of a haze, and it's a large enough crowd he doesn't see them again. Papyrus, once he's found his brother, is difficult to tear away from other people, but he's desperately craving some solitude and he's worried all this noisy clatter will drown out the memory of what just happened if he gives it a chance. Or maybe he should let it.

But soon enough, they can leave. It’s done, it’s a memory. He doesn’t remember the journey back. Papyrus is in his room on his computer and Sans is in bed, red pencil in hand, lying to himself that he'll get some grading done tonight. Mostly he's just staring out the window. What a bunch of bullshit. If person A kisses- no, _doesn't_ kiss person B, but person B _feels_ kissed, then it follows that person A _did_ kiss person B. True or false? He's grinning. He's not gorgeous, they are. Oh, stop it, they're making him blush. He flops back onto his pillow.

He thought that this was going to weigh him down, put him on the spot, or make him paranoid. But it doesn't. For the next few days, he actually breezes through work and finds himself being effortlessly cheery to anyone he comes across.

Nothing... really happened. Except he knows. He knows somebody likes him. _Likes_ him, and they really shouldn't but why can't it brighten his day? Why can't he just be fucking happy? It's nice, it's stupid, it can't happen, but it's still _nice_. Having someone want him that way.


	3. Phase Transition

**Notes for the Chapter:**

> Let's start earning that content rating, huh?

He has to do the obligatory professor thing. He notices that the average is shockingly low on the latest test. It's one of his least favorite parts of the job, trying to motivate his students to study harder. Makes him feel like a hypocrite. Not only has he still not finished grading their first exam, he knows better than most what it's like to _know_ when something needs doing and watch it slip away. He’ll get it over with fast.

"uh, so this last test stunk so bad the cops came by my house and asked me where the body was. if ya didn't pass, please for your own sake sign up for one of my office hours so we can figure out what went wrong so you're not left behind. i'll have the sign-up sheet outside my door. k. now. physics, i guess."

Over the rest of the afternoon and over the next few days, he keeps a wary eye on the clipboard, watching each slot gradually fill up. He's willed himself not to look and see if the human he _didn’t kiss_ passed or not, since he didn't really pay attention to whose test he was grading, but there's only a few slots left now and it's looking like either they passed or, if they didn't, they're not gonna come to him for help. The latter possibility makes him sick. Actually, most of the possibilities he can think of kind of make him sick. If they don't show up because they passed, he doesn't get to see them, but at least that's as it should be. If they don't show up and they failed, they may have decided it's too weird to come to him for help, given... everything. And that would keep him up nights, that kind of failure. If they do show up, he's not sure what he's going to do. Ideally, the right thing, but given the direction of his thoughts over the last few nights, he's not so sure of himself anymore. Then they swoop in so fast he almost misses it and write their name in the last available slot. As soon as they're gone, he grabs it off the thumbtack and pores over it to find the date and time he needs to steel himself for.

There’s a tone of finality to it, being the very last slot. Every other student, he tries to lose himself in helping them. It’s not too hard. He knows them all by now, he knows who needs to be told to focus and who needs to be motivated more. He brings out their paper and for half an hour each he goes over the answers. They’ll say “oh man, the fuck did I do wrong?” And he’ll point out “here’s the fuck you did wrong” and everyone, more or less, leaves having been correctly tutored.

The end of the week comes and so does his last appointment. He’s done so well with the others, or at least well enough, but he hasn’t been able to stop himself from speculating on this. He tells himself it’s a good thing. Think about it, get it out of his system. Sure, get to sleep by imagining himself trying to pin them against his door the moment they walk in. He almost laughs aloud. Trying to be predatory is hard when you’re his height. It’d be laughable.

Exactly. His advances are laughable. Nice, good job, Sans.

The time comes so suddenly that the knock on his door makes him drop his pen, and he snags it out of the air with magic back into his hand without thinking. Nerves. Shhhhit.

He puts the pen down normally as they come in and push their back against the door to close it.

He's doomed. He's not clear on the details of how, exactly, he's doomed, but they're biting their lip already and they haven't even sat down yet. He swivels away from them and digs through the stack for their test and answer sheet. They failed, but only just barely. He's kind of proud of them, that's not that bad for how much they had to recover, and kind of relieved. Fewer wrong answers means less time spent going over them. The quicker he can get through this, the better. His voice is artificially deep, cold, and flat as he begins.

"so uh. do you have any specific questions before we start going over this item by item?"

They shake their head and he's grateful for that small mercy. He's about 3 questions in when he suspects they aren't paying attention. He can feel their stare on him and he's not sure if he's gratified or horrified to realize it's not because they're enraptured by vectors.

“so as y’can see, ya multiplied by the variable when ya should’ve used the number of visible snow poffs.”

“Uh-huh, right.”

He starts throwing nonsense words into his explanation to test his theory. It doesn't faze them at all. He's drawn that S thing like 4 times already on the whiteboard and he's feeling a bit silly, talking to himself, so he snaps them out of it. It's almost worth it for the expression on their face when they're caught.

"welcome back. where did i lose you?"

The only answer is this thing they do with their eyes, opening them up like an innocent grazing animal and staring, like prey, back at him to the point where he feels like there’s something he should be guilty for. He hops, feeling weighted, back into his seat.

 _Come on, power through this_ , he mentally braces himself. He knows he’s sent a few mixed signals but please, play along, he doesn’t know what he wants so just make the decision for him and--

“You didn’t. Uh…”

He’s not sure what kind of answer that is until they’re suddenly closer, that’s too close, no no no no no they’re leaning-- _sitting_ on his lap--

“You’ve always had me.”

He feels their gaze searching his face and wants to believe he’s returning the blush because that line was so terrible.

"uhh, uhh kid? this can't, uh-" but their fingers are already exploring like he's imagined so many times by now and he abandons that and all his other trains of thought as most of his body goes limp in the chair underneath them. His eyes closed, for deniability. Not that he actually has that luxury anymore, but if he can't see where their hands are going, he feels better about not stopping them. Not that they've even ventured below his waist. Still.

One of their hands cups the back of his skull and their weight shifts up on his legs (don't think about that don't don't) as they lean forward. Their breath tickles his jaw and his toes curl in his shoes. He counts the seconds and then he counts the kisses. One, two, three… One. Two. Three. Four. One might think a theoretical physicist could count higher than four, but that's an incorrect assumption in this case. He gladly loses count.

In the back of his mind he wonders what it’s like for them - have they kissed many other humans? Is it a shock, what’s the appeal here, in peppering his solid, bare face like this? He opens his eyes, just wide, cavernous sockets, and looks up at them searching for any answer he can understand. He can’t be blamed for this if he doesn’t kiss back - he _can’t_ kiss back, he couldn’t even if he wanted to.

“ _kid_ , uhh… mmh...” but it’s less of an interjection and more of a whimper. Suddenly he realises his hands are buried in their clothes, gripping on their back - when did that happen. He squeezes his eyes shut again. Their lips are soft, so soft, and so are their hands on his neck and shoulders and the errant finger that’s testing the spaces of his ribs through his stiff shirt.

“kid,” he tries again, and sounds even less sure. "kid, please--”

It’s completely unclear whether that was a deterrent or a plea. He doesn’t know. They’re mouthing against his jaw and making little sounds of wanting.

“Oh fuck, Sans. You have no idea what you do to me.”

His eyes open wide, and it's a damn good thing all he can see of them like this is the back of their head and their neck and their shoulder and a little ways down the curve of their spine, and honestly that's bad enough as it is.

"wha-- what?" he asks, shock hitting him in slow motion, he's not asking for details on what he _does_ to them, but that's how they interpret it.

"Fuck, I've wanted this for so long, I don't think I even realized at first why I needed you to like me," they whisper, their lips never quite disconnecting from his neck.

His grip on their shirt lessens until his palms are flat on their back, and before he knows it, they're moving, testing. It's wildly inappropriate and he's a participant now, god help him, but if he's going to go down like this, he might as well enjoy it a bit, first. Better yet, he earns a gasp from them and they scoot closer, something he hadn't thought possible. They try to grind against him, but there's too many clothes in the way, and anyway, there's nothing down there just yet. His breath catches anyway from the intent behind it.

Whereas a second ago he was relieved by the absence of responsibility with his inability to kiss back, suddenly it's done a 180 and he wants to. Badly. He nuzzles his face into their neck instead.

"shit. shit, shit-- _shit_..."

He didn’t mean it for their benefit, but the swearing seems to urge them on. The moan against his cheek is the most damning thing he's ever heard. He can't think straight. Or at all. And he's not controlling his body well enough, seeking warmth and leaning in to where their chests, hips meet-- his hands are doing their own thing, fingers scraping against their back.

"al- always _liked_ ya, i just, fuck--" he's wincing and burying his face as he nearly hyperventilates. "i just... thought..."

The words ' _how could you like me_ ' have already died in him, much like his sense of decency.

It still doesn’t quite add up for him, they shouldn’t like him, this can’t be happening, even as their fingers are working the buttons of his wrinkled, probably half-dirty shirt. They don’t seem to care about anything but getting his shirt open and -- oh. Warm, soft. Even just the feeling of the pads of their fingers on his ribs, and -- _fuck_ \-- his spine and he wants skin. More skin. But how can he? He is so trapped, he can’t be the one to take things farther, but he needs it. So he nuzzles harder, holds them tighter, like that’s gonna make it any better.

They pull away and he sees their face for the first time since they first kissed him. Oh, he should not be seeing this. Students normally aren’t seen panting and aroused with pupils dilated to the size of dimes in professional contexts. They lick their lips.

“Why won’t you touch me? Please. I don’t care where, just…”

They guide one of his hands under the hem of their shirt and his eyes track the motion.

He just sits there, watching his hand move to someone else's whim. Maybe if they guide him, if they do it all, maybe then it's not his fault. Maybe he--

His knuckles brush against more skin, even warmer, even softer. Fuck, it's the softest thing in the universe. It's so different to him and his jaw is clenched so tightly he just can't maintain the lax expression he so often wears.

"b- beh-- because..." It's a struggle to pronounce anything more than vowel chains. "because. we." He forces himself. There's sweat on his cheek and now he's conscious about that as well. He's leeched enough of their warmth to be hot, and he lets his small hands settle against their waist, bone on skin. "we. _can't_."

He said it. He feels a rush and he wants it to be relief but it's not, it's arousal and he shuts his eyes again and hears his knees clack together.

"I remembered more about electromagnets than I thought I would," their words are shuddering, but still way more sturdy than his. "I... recorded your lecture on it. I play it back before I go to sleep, and..." The insistent touch of their fingers inside his ribs leaves nothing of that sentence to the imagination.

This new piece of information breaks the flimsy resolve that had held his magic at bay thus far, and the magic rushing south to his lap unabated is not the magic of a man who can't or won't or would never. They notice, because of course they do, and their fingertips seek him out. He’s forgotten how to intake air, he can only exhale, and loudly: “haa-aaa...aa...”

"Saaaahhhns, oh my god, you--" their hand cups his goddamn bulge and tests it and pulls back in shock, leaving him grunting with need.

"Y... you have. You can. Oh fuck me."

It's one of those expressions. But hearing it right now, as he practically whimpers, one hand climbing their thigh and seeking out the source of heat between their legs, it might very well be an invitation.

His mind is in pieces, so his body takes over. He’s dry humping them from underneath and there’s little satisfaction in it but for the motion of what he’d _rather_ be doing. He matches each desperate thrust with a string of words; some of them are coherent, some of them he hopes _aren’t_.

“i fucking - can’t fucking - never woulda imagined - god, i need - so fuckin’ perfect right now you’re…”

The fragments he's spluttering out, he realises, are throwing fuel on an inferno. Given that this complete mess straddling his lap just admitted to masturbating to his science drawl, his voice itself is probably doing way more to them than his hands tenderly ghosting around to their back, and lower.

"fuckin'-- can't stop wantin' t' look at'cha, don't fuckin'... ffffuck, want... 'nyone else…”

This is getting dangerous, moreso than it already was. Shit. But now that he's found an outlet in running his mouth, it makes it easier to keep his mind of the heat cresting out of his hips and making his clothes all of a sudden too tight.

“Yeah, yeah, yeahyeahyeah,” they chant, breathless, in his ear. “Oh, god, fucking touch me, I don’t _want_ anyone else, I’m - nngh - yours, I can’t -”

They prod at his cock more firmly to find where he’s sitting, then rub him gently. He’s going to let lust run his mouth if he isn’t careful and nearly chokes holding in a moan.

They discover that with his shirt open, there’s nothing to stop them from just reaching inside his pants and touching him directly, and doing so nearly sends both of them out of the chair. Humans have a bit more volume, though, and he has to work to return the favor. His fingers are stubby, clumsy. The fabric of their pants is stretched tight over their crotch and there isn’t any give, but they moan against his shoulder anyway. He plucks at the button to no avail, but they help him, shaky hands fumbling and it comes undone. He looks up. He needs to see their expression. His palm is flat against their belly, aligned with the red marks left by their waistband. They’re biting their lip and he’s never seen anyone look so helpless. Their eyes wrench shut as his fingertips peel back the top of their underwear.

And right then, in the aching recesses of his soul, he knows he’s at the end of the line. He stares, stares hard at their face, sobering. He takes one last moment. Their arm is partly inside him with their hand trying to figure out his pelvis. His fingers have just breached their waistband and there’s nothing further down but skin, warmth, the really humid kind. He grazes his thumb along their stomach so he can take that expression in. They’re just… giving themselves up for him. Entirely. They would do anything for him. Their hair is so messy, they look breathless and heated like they’ve run a mile. Their eyes aren’t even focused.

He did this to them. Somehow.

He does it slowly so they don’t get scared. He pulls back his hand, tugs their clothes into a more modest position. He touches the top of their arm, the one that’s messing with him and trying to promise whatever he needs, anything at all.

“kid. stop.”

The authority in his voice chills through the heat in the air between them. Finally his senses are returning and he knows they’re in his office, the door’s not even locked, there’s probably people walking past out there right now.

Without another word they withdraw themselves and slide off his lap. They start properly rearranging their clothes. Sans does his shirt up and grimaces trying to adjust his hard-on back into submission.

They don’t say anything. He can’t tell if they’re too embarrassed or what. They don’t exactly look confused - and hell, he’s gotten good at noticing every minute motion in their face by now.

“look. whatever i was sayin’, uhh, just there… whatever i’ve been thinkin’ aboutcha, it… wasn’...” He tries to swallow. His voice is cracked and dry. “i didn’ want it t’be feelin’ ya up in my chair--”

That’s not what he was supposed to say and he knows it. That really isn’t what he’s pining for and he probably shouldn’t say that either. What’s more awkward anyway, the base urge to fuck in an office, or one participant’s highest fantasies mostly involving cuddling?

He's glad they don't seem bothered or thwarted or... vengeful, thank god. But that does leave him wondering just exactly what they do want from him. He's aware of the clichés, the student sleeping with their professor for grades or favors or just a check mark on a bucket list, but he wouldn't put money on that being the case here. No, instead he's worried they're only chasing sex, which, he is fully aware, is an incredibly dumb thing to be worrying about when he's just come within a hair's breadth of completely debauching one of his students in his fucking desk chair, but there it is. Not to mention the insistent idea that beggars can't be choosers and he should just take whatever he can get and count himself luckier for it. And he is seriously considering it, but that might just be his dick talking. It's making some compelling points.

They're looking at him expectantly. He writes his phone number down on a sticky note and presses it into their palm. They chuckle at the archaic gesture and it makes him feel so old.

"pick a place, text me, and we'll figure out a time and we'll... talk." Their face brightens a little bit too much. "an' i do mean talk," he quickly adds, clearing his throat.

They shrug his sternness off and carefully fold up the note and place it in their pocket. When they leave his office, they’re still trying to suppress a big, dumb grin. He watches them exit the building and walk across the lawn through his window. They stop, check their surroundings, do a little victory hop complete with fist pumps, and keep walking.

He decides it's time to head home.

He hopes, not really for his own sake, the text comes soon. He doesn’t like to leave things not dealt with. This is serious, he reminds himself - this just became something VERY serious - as he checks his emails were sent, files everything he needs in his briefcase, and gets his coat. He takes it off its stand and stares at it before putting it on. It’s a really twee jacket that’s not really ‘him’, but he wanted it to make himself feel more like a professor on human terms. Hit the visual cues of someone smart and respectable, in case the rest of him didn’t follow through.

Sighing, he dons it and shuffles out of the office.

On the journey home he thinks a lot. He’s too distracted to teleport. Part of him is in utter disbelief that what happened actually happened. The other part, now that he has enough space to keep his mind straight, is ashamed. Again, he asks himself _what they could want_ from this. Do they even know him? Do they like him? Are they in that stage of life where humans just want to fuck, like, constantly? What does _he_ want from this? That encounter embarrassed him more than it gratified him. Although. It did gratify him a little. He continually catches himself touching his face on the places he remembers being kissed.

What does he want to do?

Sans only finds himself unwinding once he closes his apartment door. Finally, his bones don’t feel wracked with tension in the fear of being caught. He immediately makes for his room, ignoring the calls of “SANS IS THAT YOU” and shuts himself inside his own personal space immediately.

“SANS ARE YOU OKAY,” blasts through his closed door.

“yep, fine. long day,” he chirps back, leaning his skull into his hands as his shoulders start shaking.

Two things happen that night, right before he goes to bed.

One, they text him, naming the location: a coffee shop on the other side of town where they shouldn’t be recognized. Together they settle on a time: 4:30 Saturday. It feels a little bit too much like a date, but he can’t argue with the logic.

Two, he digs their test out of his briefcase, as if by going over it alone, he can make up for the fact that he didn’t help them much at all. They were right, it turns out. They didn’t miss a single question about electromagnetism.


	4. Resonance Frequencies

**Notes for the Chapter:**

> [slide whistle noise]

Friday passes with interminable slowness, as Fridays do, but nothing inappropriate or potentially career-shattering happens, so it meets his recently much-lowered bar for success. Or at the very least, the inappropriate, potentially career-shattering things have the decency to wait until he gets home. 

He’s sitting at the table, listening to Papyrus tell “the To-Be Legendary Tale of How Two Great Friends Charmed Every Dog in the Park into Being Their Friend, Even the One that the Owner Said Normally Doesn’t Like People” while he bustles around making dinner when Sans’s phone chimes. 

**Them:** Can’t wait for tomorrow! 

The fuck can he possibly say to that? 

**Sans:** k cool me 2 

He deletes the “me 2” because he doesn’t want them getting any ideas, sends the message as is, then realizes it’s kind of rude. And even though normally he’d be fine with being a bit rude, he decides they deserve better than that at least, so he sends it in a second message, which is worse because isn’t his reciprocated excitement emphasized _more_ that way and… fuck, he’s never analyzed a 4-word text this much before in his life. 

**Them:** Thought about you again last night… 

He turns his phone off, as if doing so could halt the instantaneous physical effects of that message on him. But Papyrus deserves his full attention, and anyway, some of the dogs in his story sound pretty great. 

The next day, he turns his phone on, half-expecting a litany of messages, angry at him for not responding, for his weak, last-ditch effort at sabotage, but there’s just one from that morning. 

**Them:** Sorry if that was too much. We still on for coffee? 

He breathes a sigh of relief. 

**Sans:** yup we’re good. hope u haven’t bean worried. 

**Them:** Wow. Woooow. Just for that, you’re buying. And um yeah, I was a little worried. Please don’t do that to me? 

It’s too early in the day to feel this many different kinds of guilty.

He actually gets some work done around lunchtime, because it takes his mind off whatever he might have to do that afternoon. Which is not a date, and was never supposed to be, but they obviously think it’s something like it, and does it become a date anyway if he pays for a couple of drinks like they joked about? They didn’t seem overly serious but the intent is clear.

He trudges around between his room and the bathroom, getting ready but trying not to focus too much or put too much effort in. What’s he supposed to wear? Not his usual professor stuff, the point is to make this more easy and relaxed. His old hoodie isn’t clean enough. He registers Papyrus talking but blanks on the specifics.

“SANS, DID YOU HEAR ME?”

“uhhh. what? sorry.”

“I SAID ARE YOU FEELING WELL? YOU’RE ACTING STRANGE.”

“how’s that, bro?”

“THE WEEKEND’S BARELY STARTED AND YOU’VE BEEN DOING WORK, FOR ONE THING. YOU ALSO LOOK RATHER TIRED AND STRESSED AND YOU’VE BEEN GOING IN AND OUT OF ROOMS AND DOING NOTHING.”

“oh. it’s nothin’, ‘s just a lotta pressure goin’ on at work.”

Suddenly he’s three times higher off the ground as normal and wrapped into a bony hug. 

“YOU’VE SEEMED DISTRACTED LATELY. THINGS HAVE BEEN DIFFERENT SINCE WE ARRIVED ON THE SURFACE BUT EVEN THE GREAT PAPYRUS DIDN’T SEE YOU APPLYING YOURSELF TO A HUMAN JOB WITH THIS MUCH RESPONSIBILITY. I’M VERY PROUD OF YOU.”

He hugs his brother back. It settles something in his soul. If he were caught, if he lost his job, it wouldn’t be the end of the world, because he’d still have this.

Papyrus drops the issue for the most part after that, only eyeing him suspiciously when he catches Sans working in the laundry closet, hosing his hoodie down with a generous spritz of fabric refresher and going to town on some of the darker spots with a stain remover pen. 

Once he's good and ready, or at least as much as he's going to be, he heads out the door about five minutes later than he should. People are often late to coffee dat- to coffee, right? It's casual, it'd be weird for him to show up at 4:30 on the dot when he can barely make it to his own lectures on time. 

“bye bro, i'll be back later.” 

“AHA! SO YOU DID HAVE PLANS! WHERE ARE YOU GOING?”

“i have a, uhh, meeting.” 

“ON A SATURDAY AFTERNOON?”

“huh, yup. guess so.” 

The two brothers stare each other down, one poker-faced and the other skeptical and calculating. Papyrus breaks first and sighs, waving Sans off. 

“ALL RIGHT, GO TO YOUR SHADY WEEKEND MYSTERY MEETINGS.” 

“k. i will.” 

“SANS, YOU'RE LETTING COLD AIR IN, PLEASE GO.” 

“k, bye.” and he's gone.

Part of him wishes Papyrus could have come along. For moral support, for humour, for just easing off the idea of this being an illicit date. But that would necessitate explaining the situation to Papyrus and although he feels like he should, he also knows you don’t tell Papyrus anything you don’t want the entire world to know. 

Guilt, guilt, guilt. 

He decides he’s too nervous to travel the regular way and pops over to the general vicinity of the right area. He hasn’t been over to this side of town as much yet, and has to wander about to find the place. When he does, though, he’s a little late, and that’s probably good, he doesn’t want to look eager, although he kind of _is_ eager and wants to see them - but doesn’t want to look like an asshole, should he have checked his phone for texts--

They’re sitting outside the coffee shop at a parasol table. He loses his breath momentarily. They’re dressed more cute-casual than they would be for class; they've put in more effort than he has, that much is obvious. His normal off-day clothes are enough, though, right? It has to be enough, it's too late to be worrying about this stuff, they’re waiting there for him. Date or not, it’s the closest he’s ever been to having one. Last time he saw ‘em they had their goddamn hand down his pants…

He steels himself and shoves those memories firmly away for now. They look up as he approaches the table, having been poking around on their phone. 

They positively _beam_.

“Sans! Hey there, handsome.”

They wink.

Oh, boy.

They follow him inside to stand in line at the counter, their idle conversation about what menu items this place is best known for (“The banana nut muffins are the size of a small planet, wanna split one with me?”) calming him down considerably from the initial shock he'd suffered at seeing them all dressed up and apparently ready to flirt their ass off from the get-go. They both move to the counter at the same time and they smirk at him, gesturing for him to go first. He shrugs it off and places his order, only for them to interrupt just as he’s pulling out his wallet and place their order as well, and then _pay for it_. They collect their drinks and reheated muffin at the end of the counter. 

“what was that about?” 

“Nothin’! You can get the next round.” 

Great, now he's committed to two cups of coffee. Four, actually. What if this goes belly-up before the first cups are drained? A quarter of the way through the muffin?! What then? Well, that's a problem for Future Sans. 

They jointly venture back outside and start picking at the muffin and blowing on their coffee. A few moments pass in silence as they people-watch. Some are walking dogs, which reminds him of Papyrus’s story, which reminds him of their text, and suddenly he finds it unseasonably warm for late October. They start speaking almost at the same time. 

“I don't want you to think- oh, sorry-” 

“i've been tryin’ to figure out- whoops, my bad, you go ahead.”

There’s a few beats where he looks at them and they look at him and it’s not like an awful social faux pas, but they both start chuckling at the same time because of stumbling over words with someone you’ve had a messy forbidden desk chair tryst with. 

They start over. “Last night when you didn’t reply to what I said, it bothered me and I thought about it a lot. I think I was pushing too hard. I just don’t want you to think this is going on for the wrong reasons.”

He feigns stupidity. “what’re those?”

“Like, that I’m bartering for better grades and that I don’t… care.”

He tries not to look uncomfortable. He thinks he does anyway because he can’t just sit there and grin mindlessly at this and doesn’t have a good grasp of a more appropriate expression.

“uhhh... oh. uh, really?” There’s a few jokes he could make but he can’t get them to form in his mouth. He sets his paper cup down and stares at it. “i’m... glad that’s not whatcha want, honestly. ‘cause i wouldn’...” God, he’s mumbling everything. Just spit something out. “’m really confused ‘bout why ya so into me. sure’s hell not used to it.”

They finish their swallow and sit forward, leaning over with their arms crossed. They’re frowning. “I just… like you. You’re clever, and you’re really funny. ...I can’t stop thinking about you.”

He can’t look them in the eyes. Not because it’s them. He never expected anyone to be talking about him like this.

“well that's, um…” he starts, smushing a crumb of muffin into the napkin with his thumb. That's good to know, it's a huge relief, if they're telling the truth, that's exactly what he's been wanting to hear, but he can't say that, not when he's still wrestling with the idea of just trying to put them off entirely. They should know where he stands.

He looks at them ruefully. “i’m just gonna lay it out. nothin’ more can happen while i’m your teacher. so you tell me where that puts us.” 

They sigh into their coffee. “That's about what I expected. I mean, I don't want you to lose your job, you're actually a really great teacher and even if I didn't have fff- well anyway, I’d still admire that about you. But you did say _while you're my teacher_? So like, next semester, we could maybe-” 

“- _maybe_ ,” he interrupts. “but c’mon, i can't ask you to wait that long. i wouldn't wanna, anyway, ‘cuz honestly you should be…” He’s tearing the plastic lid on his cup to shreds from the inside out while he speaks. “ya deserve someone who’s, fuck, umm.” 

They save him by cutting in before he lets things get too heavy. 

“You don't have to ask. You don't have to ask and I'm not gonna make you. I'll wait. Obviously I'll wait, that's only, like, what? Seven weeks? Grade my final first.” He scoffs and they slap the table in front of him. “I'm serious! Sans, I am so happy. It's not that long to wait and in the meantime, we can get to know each other better! Shit, I really thought you were gonna tell me to back off once and for all.” They’re grinning into their cup. 

“i considered it,” he says, still reeling.

“Oh.” They deflate, but only a little. “Well, I'm glad you didn't.”

“i dunno how i ever really felt about bein’ in charge of a buncha humans. dunno if it was the right idea, it seems to be somethin’ i can do, but i… i dunno how i’m supposed to act around you guys. never been too great with authority myself so it's a weird feeling to hafta balance who i really am with who i’m s’posed to be, y’know?” They nod attentively. “this is me,” he looks down at himself. “you’ve been honest this whole time, so i might as well be, too… i don’t think i know what i’m doin’. humans are weird an’ i’m still gettin’ used to ‘em.”

They nod, again, and chew on a muffin piece. “We’re still getting used to monsters, too. But I’m glad you’re all finally here.”

“so look, kid. here’s us, and we’re not gonna do this until it’s not against the rules. they’re there for a reason. y’deserve to focus on school right now. seriously.” He rubs a hand along his brow. He never likes being the voice of reason. “and… aside from that, i’ve never dated a human,” he’s never dated anyone, but they don’t need to know that, “an’ i’m gonna go ahead and guess you haven’t dated any monsters. so there’s that, too. and then, there’s… me, i’m. uhh.” He makes himself look at them. Take in why he needs to make this clear. “jeez, i dunno why you’d look twice at me. i don’t want you t’wait that long, miss out on… better options. then find i’m not what you’re lookin’ for.”

They look down into their lap. It might be pessimistic, but he’s glad he’s getting this out. On the other hand, the way this has stressed and tortured and strained him mentally, he has a faint desire to renounce it all and hug them right this second. He recalls them saying they _only wanted him_ and blushes in spite of himself. Friendly outings, dates, or bedroom, he doesn’t particularly care. He wants them too. It’s just too out of line to say it.

There’s a crooked smile on their lips. 

“You severely overestimate the quality of the undergrad dating pool at our college if you’re referring to any of them as ‘better options’.” They hazard a glance at him, but he just stares right back. “Um, I’ve meant every word I’ve said to you so far. I can’t speak for you, but I also don’t really regret a single thing I’ve done, so… I mean, you know where I stand. You’re worth waiting seven weeks for, Sans. I’m not going to wait because you’re asking me to, or because there’s just nothing better around, I’m going to wait because I have hope.” 

And he can see it. They do, and he’s just staring at them in awe. His hand is resting atop his own knee, and he feels their hand land on top of his, gentle as anything, fingers interlacing like it’s the most natural thing in the world. It’s not sexual, it’s not a repeat of the first time they came onto him, it’s just... nice. And it makes him realize how starved he’s been for this.

He slumps over until his head bangs on the table, his knuckles still gripping theirs. 

“ok,” he groans, breaking. 

“Okay as in…?” they prod. There’s that hope again. He lifts his head only enough to look at them, chin still on the table. 

“ok, but we gotta set some ground rules or i’m gonna… fuckin’... die. or somethin’.” 

They snort. “You’re not gonna die. I’ll agree to some ground rules, but I reserve the right to negotiate my terms ahead of time.” 

“i need more coffee if that’s how it’s gonna be. ya done? c’mon, i’ll buy you another.”

Well, his resolve has been eroded this far. Now that he’s actually agreed to something, it finally feels a little safer. He could really do with a nap, and maybe a nap partner. The fingers intertwined with his promise something. He squeezes their hand. 

“If this has to be an agreement, maybe we should write it down?” They continue. “Do you think we should have lawyers present? If I have to sign my name to something, I only have one stipulation and that’s no fisting on Sundays.”

Sans seizes up rigid and cannot breathe.

“Sans? ….Sans. I’m joking.”

He coughs. “shame, that's a solid rule. i think we should keep it.” They tip their head back and laugh, glad that tensions seem to be loosening. 

“In that case I’d suggest we amend it to include all major religious holidays.” 

“and bank holidays.” 

“And Talk Like a Pirate Day.” 

He’s never heard of that one before. “you drive a hard bargain, but i’ll let ya have that one.” 

They turn their manic, teasing grin on him. “Are you suggesting that were it not for the Rule, you’d be all for fisting on Talk Like a Pirate Day?” 

He slumps down in his seat. _Think_ , Sans, _think_ before you speak. Sure, they're obviously just joking, but has he really lost the ability to go five minutes without accidentally making an innuendo? It's upsetting, usually he does that on purpose and only when the timing’s right. “fuck, that's really not what i meant, i was just.” 

They give his hand a reassuring squeeze. 

“If I had known you'd be this easy to mess with, I would have started a long time ago.” 

“i’m really not, usually. think it's just you.” He gets a sympathetic, grateful look for that. “usually i’m the one that messes with people, so.” Then he notices them staring at his hands, and he lets their hand go quickly and brushes himself down before going to get another coffee round. He pays for both, so they’re even now. 

Finally, they start agreeing on the actual rules. No romantic or sexual behaviour at all, for the near future. No flirting in class, that goes without saying. No telling anyone at their establishment about the possibility of a relationship. No incriminating texts whatsoever, and they both delete their current short message history. 

“and, uh, if ya find anyone else ya like in the meantime…” Sans tries to sound nonchalant, drumming his fingers on the table. “it’s.. y’know. no pressure.”

“I kinda doubt it, but. Understood. And if you suddenly find a nice monster girl, umm…” their tone had been light, but it takes a serious dive as their face suddenly falls. “I’ll.. Well, I’d probably… get over it someday. Uh, no pressure either,” they quickly add.

He can't help but be a little delighted to hear that. Not that he didn't mean it when he said they should keep their options open, but it's good to know they're in the same boat as he is as far as potential heartbreak is concerned. Still… 

“aw, that’s not the same. i'm not gonna, i mean. look, you can hold me to my end of it. it's you that's gettin’ the short end of the stick. i don't need an out.” 

“Well, neither do I!” 

“ok, you say that but there's still a lot ya don't know about me, yet.” 

They drag their hands across their face. “Oh my god,” they drawl, “are you always this stubborn?” 

“who, me?” 

“I'm looking forward to getting to know you and all your horrible secrets and telling you mine. So you can take your martyr complex, and shove it up your ass.” 

“don’t have one.” 

“Then it should be easy for you,” they say, rolling their eyes. 

“don’t have an ass, either.” 

They snicker behind their hand until the laughter fades and they’re left staring at him and sighing. “So what do you say?” 

He rolls his neck, deflecting as much as possible. 

“yeah, yeah, i trust you and junk n’ stuff and i uh. i wanna do this right, so you got it, no pressure.” They nod, seemingly satisfied. 

What's left of the coffee in their cups is cold, Sans has two demolished plastic lids in front of him, and they’ve both long given up on the muffin. He shifts uncomfortably in his seat. 

“i, ah, should probably head home. i wouldn't tell my bro where i was goin’ this afternoon and the longer i’m gone, the more questions i’m gonna have to dodge, so…” 

They stand at the same time he does. “I've got a nosy roommate, too. Okay, well then, I'm really happy we did this. I’m so glad you're, uh… that you want to, y’know... this is better than I'd hoped for and…” the color rises in their cheeks and they’re making a careful study of the peeling rubber coating on the picnic table, “I just reallylikeyou a lot and I wannabewith you? And-” 

He feels dizzy, lightheaded. He has to stop them. 

“kid. please.” 

“Sorry. Right. Rules. Just. Just give me one for the road. Please.” Before he can ask what they mean, they're bent over, holding him close, lips as close to his cheek as they can get without touching, how do they even do that, but it's just like at the gala. “If this is all we get for the next seven weeks, we'd better make it count, right?” 

He wraps his arms around them and they press a real kiss to his cheek, then another, which he thinks is cheating, but he’s in no position to say anything. The embrace is both too long and nowhere near long enough. They pull away, unsteady and shy. 

“There. And now we'll both be good.” They wipe their sweaty palms on their thighs and back up a few steps, digging their car keys out of their pocket. “Um, I'll see you in class on Tuesday?” 

“yup.” 

His voice is tight, strangled. That's about all he can manage for now. He watches them get in their car and pull out of the parking lot.

He bids them farewell in his head. For the next two months.

He takes his time and doesn’t go anywhere right away. He hovers on the corner just down from the shop and stares at the table they were at, trying to imagine what it looked like to a passer by. They didn’t stand much chance of being recognised over here, but there weren’t too many short skeletons in the world. 

Eventually traipsing away, hands in his pockets, Sans wanders in god knows what direction. He’s still bubbling with elation over the promise of something real, something he could, eventually, be proud of. Adding the way they held his hand under the table to his mental list of nice, affectionate things to remember. There’s nothing to worry about in class for the future. They’re on the same page. 

After taking a path through a park swarming with dogs ( the one Papyrus went to, perhaps?) he eventually runs out of stuff to think over and decides to get home. The line about his brother was more to avoid a drawn-out goodbye, but still, it’s true he shouldn’t be out on his ‘shady weekend mystery meeting’ for too long.

He blips back, next to their front door, and shuffles in. Papyrus is right there in the living room, watching TV.

“hey. ‘m back.”

Papyrus doesn’t look over. “HELLO, SANS, HOW DID YOUR DATE GO?”

“it was fine, actually, they didn--”

Sans swears and clacks his hands to his face as Papyrus jumps up and squeals.


	5. Linear Momentum

**Notes for the Chapter:**

> Hey folks! My Friday involved eating burgers and seeing friends and getting my life destroyed by watching Grave of the Fireflies for the first time. It did not involve much of getting this chapter ready to publish. So here it is now.

**Week 1**

Papyrus's enthusiasm, predictably, carries over well past the first confirmation of his suspicions. He draws details out of Sans over the rest of the weekend, one at a time. Sans being Sans, it's a painstaking process, but now he knows their first name (he's working on getting the last name so he can google them, Sans sometimes associates with the most dubious people), their favorite color (though he suspects Sans doesn't actually know and just made something up to appease him), and an unsatisfyingly vague and not-nearly poetic enough description of their general appearance. He’s still missing so many pieces of the puzzle, the questions Sans refuses to answer tell him more than the few answers he does have. For instance, how they met. Sans doesn't just change the subject for that one, he attempts to create an entire diversion, which would, on any other day, bring warmth to Papyrus's very soul, but in this case it frustrates him more than anything.

But he has time. Sans seems invested, so he figures he has enough time to find out what it is about this human that’s had his best and only brother so out-of-sorts lately. But for Sans, all of that discomfort is mostly behind him, facing this next week of classes. He’s optimistic, a truly alien feeling for him, and it has him feeling odd in his own body. He finds out after the first day of classes that no, he doesn't actually have more energy than usual, he's just been more willing to spend it on things he wouldn't normally. He’ll have to be more careful about that if this pattern continues.

Exhausted, he goes home early that Monday, sparing a yawned greeting to Papyrus before he locks himself in his room. He manages to squeeze out one email before closing his eyes. It's to them. He keeps it professional, offering them a make-up office hour for the one that got… rained on. They accept the appointment almost immediately and he goes straight to bed.

When they show up at his office, he’s not dreading it. He’s nervous enough, certainly, but he's not afraid of them or of himself, it’s just that he suddenly finds himself more than usually conscious of what he looks like, what he sounds like. It’s unnerving. He catches them staring at him again while he's explaining, their pencil limp in their hand and their notes neglected.

“kid. c'mon.”

“Aah! Sorry!”

“i’m more than just a pretty face, y’know.” That earns him an eyeroll and a begrudging grin. 

He picks back up from the beginning of the last problem, blush tinting his cheeks as well as theirs, and the rest of the appointment is all business except for the unspoken but palpable acknowledgement of the change in their relationship. He feels lighter. He can't remember the last time he’d enjoyed going over a failed test quite that much.

**Week 2**

He has to make sure he has enough time devoted to his other students as well. Remembering this allows him to resume more or less the rota he had before. And by this point, he really doesn’t feel awkward about being straight with all of them. After all, apparently it’s something that’s likable about him.

The only thing really on his mind now, and it’s not bothering him per se, but it’s more of an unsolved problem, is just how _they_ ended up so distant, every time they join him for a private session. He hasn’t seen it in any other student, but for some reason, he’s… attractive to them to the point of complete distraction.

How? It makes no sense. 

Papyrus continues to ask lots of questions but Sans learns the best way to deflect them - by asking Papyrus questions of his own. This quenches Papyrus’s need to talk about it but lets Sans pick the subject, and directs it to himself rather than anyone else. Does he have good enough clothes to date in? What do humans usually bring as a gift? Does he _really_ need to shower?

It’s enough, and it keeps his brother occupied for the time being.

**Week 3**

He’s packing up his gadgetry from the lecture, clearing off the podium for the next section when he notices a grey scarf draped over the back of one of the chairs. He nabs it on the way out and takes a picture of it.

He sends an email to the whole section: “someone leave this? speak now or forever hold your peace, it’s warm and i might just keep it.”

He receives a few replies that make him chuckle. He really does like these kids.

“Oh no! It’s starting to get woolly cold out! Hope its owner isn’t missing it!”

“I wouldn’t blame you, we all yarn for a good scarf now and then.”

“Whoops. That’s mine.”

That last one isn’t funny in and of itself, it’s just that it’s theirs. Of course it is. He makes sure he’s not replying to all.

“i’m going up to my office for now. come and get it when you get the chance.” They send him a text instead of replying to the email.

**Them:** Ummmm… 

**Him:** you know what i meant. i’m leaving it on the coat hook in case i’m not here when you swing by.

They come just as he’s finishing up his last appointment of the day. While he packs up, they wrap the scarf around their neck and inadvertently cause him to forget what he was doing. He takes a moment to stare. It’s not against the rules to look, right? Or maybe it is, he kind of can’t remember. He walks out to his car and they walk most of the way with him, turning to go into the library at the last second. 

After the next class, there’s a navy blue scarf on the same seat. Suspicious. No, not suspicious. Obvious, really.

He snaps another picture and sends it directly to them in a text: gotta be more careful, i might start to think you’re doing this on purpose

**Them:** Who, me? Yeah, I’ll Come And Get It later.

Papyrus learns from Sans that they have excellent taste in scarves. He’s never known Sans to notice what kind of scarf someone is wearing, let alone have an opinion on such a thing. Must be one of his odd jokes. 

**Week 4**

This week gets off to a good start, which is nice because he’s hoping for no more shenanigans. He can’t get too distracted, he’s got more students to consider than just that one, and like hell does he want to let them down at this important juncture in their lives. God, honestly, who got him so invested in the lives of human kids and why did he ever get suckered into it?

On Wednesday he finds another scarf. This one in the library. Light blue. He just sighs this time, defeated, and sends another text.

**Him:** you have too many scarves, kid.

**Them:** Oh, shoot. Really didn’t mean to leave that one. Don’t need it, don’t worry

He hangs it up in his office in case they come by, and they don’t. So he brings it along to class the next day. For some reason his nerves kick in as he waves the students away, as if any of them are going to read something not so virtuous into him motioning his favourite over and pointing at their abandoned garment.

“I think you were right, I have too many scarves. That one’s old anyway.”

And they just leave. In his confusion, he watches them go. Then he snaps out of it and, as if it’s natural progression, tucks the scarf around his own neck.

Oh.

It smells like them.

The shock of it makes him lose himself in the very vivid associated memory. When they were in his lap and bucking on top of him and he was getting kissed and he was a second away from shoving his hand into their pants and---

Pushing back against those thoughts, for the sake of the grim acknowledgement that he can’t jerk off in a lecture hall, he gets out of there as fast as possible. Not that he takes the scarf off, though, come on, it’s November.

He’s still wearing it when he walks through the door at home and he scrunches up and pouts when he sees Papyrus’s expression.

“SEE, I KNEW THEY HAD GOOD TASTE!”

**Week 5**

The end of the semester is three weeks away. Three weeks isn't such a very long time, except when it's the end of the semester. Faculty and students alike are sluggish, burnt out, and Sans thinks it must be contagious because he's moving even slower than usual.

His mind is too, apparently, since he forgot to bring lunch for the second time this week. He’s already holed himself up in the dimly lit cafeteria once, on Monday, and that wasn't a pleasant experience for anyone. So perhaps something else, something he can eat quickly while looking out a window. Windows are important. He wanders over to the campus run cafe, he has a special weakness for their bagel pizzas.

Once he's set up in a table overlooking campus, lazily munching on his pizza and trying not to get grease stains on anything not easily covered by his jacket, he rests his head in his hand and lets his tiredness overwhelm him. He's looking forward to the end of the semester for more reasons than one, although one of them does stand out from the rest, but it's just far enough away to be utterly discouraging.

Zoning out, he sees them and his mind stutters before chugging back to life. It's not weird that he'd see them, it's a relatively small school. They haven't seen him yet, though, even though they're headed his direction. With a friend.

One of his advisees, actually. Smarter than him, probably, if he's being honest, and to all appearances, a decent enough guy. The sort of person they should be dating instead of holding out for him.

No. He shakes the thought off. No use going down that path when he's still got two more classes to teach after lunch. Until he watches them part ways with a hug and a kiss on the cheek. Okay. That was. No, it's fine. There's no reason for him to even read into that. Maybe they’re just touchy with their friends.

Maybe not.

Maybe they got tired of waiting. Maybe they realized they’d be better off. Maybe they’re just naturally falling for someone else. Good. Good. That's what they deserve. That's why he gave them that option from the start.

It doesn't feel good, though. Why the fuck did he not prepare himself better for this? Why did he ever bother thinking it might turn out any other way?

And he can't deny, he's frustrated. He has no right to be, but they said they'd wait! They told him! They’d been so sure, he'd felt their certainty.

Shit, shit, they’re coming his way, they’ve seen him, he’s gonna have to talk to them in person in public-

“Hey, you all right? You look like shit and you've got, uh, a string of cheese on your chin.”

They're being very quiet. He wipes his chin with a paper napkin, but can't look at them, they'll know that he knows, and they'll feel guilty and he doesn't need that. Neither do they. 

“yeah, ‘m good. ya need something?”

They frown, shake their head, and go buy their lunch.

About an hour after he gets home they send him a text.

**Them:** What was up with you today?

**Him:** indigestion

**Them:** I am going to call you a liar in just a second, but. Is that even a problem you’re capable of having? Serious question, btw. Oh, yeah. And you're a liar. What's wrong? Also serious question.

He tries at least three times to write something, but he doesn't know what he even wants to tell them. While he's sitting there with the cursor blinking just behind the single letter he's successfully typed, an ‘i’, his phone rings in his hands and by sheer habit alone, he answers.

“You're taking too long and I'm worried. You've gotta give me something.”

He takes a deep breath.

“i don't wanna go into detail, but just consider this your friendly weekly reminder that you're under no obligation to wait for me. i’m not gonna mess with your grade or anything if you wanna call it quits before the end of the semester. i won't be mad.”

They're quiet for a moment, and he hates this, he _hates_ it.

“You wouldn't be mad?” Their voice is tiny. Fuck.

“no. i wouldn't be mad.” Not at them, anyway. 

“Do _you_ wanna call it off, is that what this is about?” they ask, almost bordering on a shout.

“no, what? god, no. no, i just. wanted to make sure you knew that was an option you still had. i thought maybe you'd found s- y’know what, it doesn't matter what i thought, it’s still true.”

“Why would you think I… OH. OH! OH MY GOD!” He hears them sniffle. Wait, did he make them cry? Fuck. Only now they’re laughing. “Sans, you got jealous over a little peck on the cheek?” They laugh some more.

“uh.”

“And here I thought you didn't care at all and… and oh my god. No. No, I'm not gonna run off with fucking Ben or anyone else, especially not when we're so close to the end.” Their voice drops a bit. “I've said it once before and I'll say it again now for your benefit. I don't want anyone else. Just you.”

Shivers run through him. He has to clear his throat before he can so much as scratch out a noise.

“ok.”

“And Sans?”

“yeah?”

“Maybe get a grip.”

“‘s good advice,” he croaks. They hang up and he's not in the least surprised to find himself hard.

Something about their tone has him reeling. He could barely even speak just then and uselessly covers his mouth after putting the phone down. They just told him that even though over a month had passed, they still really only had eyes for him. And then they, a student, had flatly reprimanded him. The curt, assured finality of their parting words was… he can’t think about anything else.

Sans hops onto the edge on his bed and eases his thumb along the curve gently glowing in his shorts. He hisses, only one eye cracked open.

He’d just been assured by a human that they would renounce their peers, even their own species, to keep on waiting for him. And if he’d decided to make it a longer target, the deliberate flatness in their voice told him they’d have accepted that, too. He could make them wait, and wait, and when he was ready, they’d be there, and finally, they could be together, he’d--

He whimpers, loudly, the result of properly touching himself, and tries to cover his mouth with his free hand harder. He can’t remember if Papyrus is even home right now and he can’t - can’t - face that kind of accidental embarrassment. Sans takes his hand back, using both to clutch at his sheets instead. Get it together, Sans. 

His mind’s eye has other ideas and decides to remind him how badly he wants his own student on top of him. Grabbing at him needily, impatient to have their hands on him. His knuckles are bunched up in the sheets. He’s gagging for it so badly he can’t even pretend in his imagination he’d last longer than five seconds. He’d warn them, of course he’d try, but there they are in his head, sitting bare on his lap, taking him inside, and calming him, breathing encouragement and understanding in his ear as he loses control without even moving--

The building wetness trying to assert itself at his crotch, angry at being ignored, reminds him to stop. He forces himself to sober up before he gets a stain. Not right now. Not yet. This is a luxury he can’t afford if he wants a fighting chance at keeping his growing affection for them a secret. Not to mention it's still wrong. Right? 

He’ll last, no matter how much he wants it.

Probably.

He squirms and takes deep breaths until he can control his magic enough to dissipate his manifested arousal. He can do this. It will be easier this way.

**Week 6**

Just another fortnight, he reminds himself every time he gets bored grading a practice paper. Just that, and then he can stop pretending he doesn’t think about them every second his mind gets to wander. That’s not too long, except of course, this two weeks is apparently longer than everyone was waiting to get out of the underground, or hell, it feels like it.

He still wears the scarf out, but not when he has to teach _their_ class, just in case.

Honestly, he thinks, as he wraps up a session and makes himself not look towards their chair too often-- honestly, it’s a good thing he loves _this_ kind of science and not chemistry. Because if he had to talk about bonds and attractions and reactive things, he probably wouldn’t be able to do it with a straight grin. Or, god forbid, biology.

One good thing about the waiting period, aside obviously from it assuaging his conscience, is how firmly it’s cemented his decision to pursue them once he can. He has no doubt any more about his own intentions. He truly wants it, there’s no escaping that any more, it’s just a matter of time and… well, after that phone conversation, he doesn’t see them likely to lose interest. Probably. He hopes.

They approach his desk as all the other students file out. Oh, god. It can’t be about the mistake he made the other day, they’re not going to torture him, right--

“Hey. Just checking,” they sound barely interested, doing something with their phone, “the assignment from last week, did you want that next session, or did you want it now?”

Sans gestures to the pile of handed-in papers at the edge of his desk. “i want it now.”

“‘Kay.” He watches them pull a paper of their own out of their bag and place it on top of the pile. Then as he keeps watching, with their phone angled so he can just barely see the screen, they press the stop recording button.

“See ya.”

They bounce away like all they care about is going to lunch.

He is, actually, going to die.


	6. Inertia

**Notes for the Chapter:**

> Thanks for all the comments, kudos, bookmarks, and unspoken well-wishes, you folks are truly the best!

He's prepared. He's been grading like it's his only purpose in life, so he can be caught up by the time their section’s final is over with. Then, he just has to run the tests through the scanner and enter the grades into the system, and they’re no longer his student. 

Maybe it's the stress of trying to do all his grading at once, maybe it's the departure from the routine he’d settled into (never in a million years would he have guessed he'd feel comforted by a routine, but there he is), maybe it's the weight of the memories he's been neglecting. In the wee hours of Thursday morning, he wakes up, sheets damp with sweat, head pounding. Papyrus is sound asleep in the next room, but he still feels exactly as alone as he does every other time this happens. He checks the time on his phone. 1:00 AM. 

He scrolls through the list of recent calls. It's a long list of Papyrus's name, but hidden close to the top is theirs. He touches their name, and they pick up on the second ring. 

“Hey…” 

He can hear other voices in the background. He didn't plan this far ahead. He says nothing. 

“Are you okay? Sa-uhh, just a sec, lemme get somewhere quieter.” The voices fade and he hears wind. “Sans, are you all right?” 

“‘m fine. just nee- i just wanted to hear your voice.” 

“Well, that's sweet but you sound kinda rattled, and this isn't really something I’d think you’d… This just doesn't seem like you, is all. Are you sure you're okay?” 

“yeah. can't sleep. how d’ya mean?” 

They laugh softly into the receiver. “I would have put money on the first person out of the two of us to make a late-night phone call being me, is all. I'm not as good at these rules as you.” 

“seems like you're havin’ fun findin’ loopholes, though.” 

“Who, me? That's quite an accusation.” 

“well, i’m a good judge of character.” 

He can hear crickets in the comfortable silence that falls between them. 

“where are you?” 

“I'm just outside my apartment. We're having an all-nighter and it was getting kind of loud in there, plus I didn't think it’d be wise to uh, talk to you in front of all of them. Why?” 

“shit. shit, i’m sorry. i wasn't thinking, of course you're studying. uh. sorry. go back inside, finish studying, don’ worry about me. i'm fine, i promise. s’nothin’, just a bad dream.” 

They sigh. “I kinda feel like you wouldn't have called me unless it was serious. You're like that, it seems.” He protests some more, but they cut him off. “No, look, we're not getting any actual studying done, haven't been for hours and when you called, they were talking about going to fucking Waffle House. I'm ready to chalk the night up as a waste. I can come over if you need me.”

There it is, right there, the exact words he was longing to hear. He may not have had an agenda when he pressed their number, he may not have even been hoping for it, but the kernel of warmth in his soul tells him everything.

“i uh,” it’s just instinct at this point. “i can’t. ask ya to…”

Because he knows it’s wrong. It’s all wrong. Everything he’s ever wanted is wrong. He just wants to see them so much right now, his magic, which is twisting in his gut as his emotions try to find a way to stabilise, might just take him there automatically. But he clamps down on it, holding himself in check, curling up and still sweating and cold. 

“i don’t think that’s the best…”

Silence down the line. They haven’t said anything. Just waiting. Waiting for him to finish a sentence. 

He’s so tired of this. It’s been 7 weeks since he got those last two kisses, and they’d nearly made it. They were so close. But he’s so exhausted, worn out from the workload and worn out from the irregular sleeping schedule because he keeps waking up, unstable, unfocused, just gross and awful and so, so tiny. He doesn’t want Papyrus to worry and has never mentioned it. He should be able to deal with this. Alone. 

But he’s so, so tired of being alone. 

He’s not crying. It’s just that his voice comes out torn and it carries on a sob. 

“i need you.”

“Okay. I’m coming.”

“oh god. no, no. i don’t- i--” He sounds like an absolute mess, he doesn’t want to talk any more.

“No. Shh. It’s okay. Calm down, where’s your place?”

He lists off the address, knowing it’s not all that far from campus, it won’t even take long. And then the phone beeps. They’re gone. 

He doesn’t know what to do. He can’t calm down. He’s still jittery, he can’t keep his hands still, and now he’s got to sit and wait. This is just one of those nights, just like so many before it. Or it had been until he called them.

He glances at the clock, and his phone buzzes. 1:30. Of course they aren’t stupid enough to knock.

He twists the knob all the way, puts pressure on the hinges as he slowly opens the door so it doesn't squeak. They come in noiselessly and he shuts and locks it again with as much care. 

He doesn't have to face them, they’ve caught him in an embrace from behind. After a moment, he lets his spine sag against them. Now that they’re here, his mind’s calmed down some, enough to make him consider sending them right back out the door, back to their friends and the Waffle House. Normal things for someone their age, in their position. Then they turn him around to face them and squeeze him a little harder and all he can be is glad they came. 

They speak first, in a low murmur. 

“Do you wanna talk about it or do you just wanna, um,” even in the relative darkness, he can see their awkward blush, “go to bed? Back to bed. Whatever.” 

“uh. i’m gonna go to bed. you don’t have to stay, though.” He wants them to stay. 

“I know. Lead the way.” 

He’s too tired to be self-conscious about his room, it’s dark, and anyway they’ve seen his office, which is arguably worse in many ways. They’re probably more familiar with the state of his office than most. 

He crawls into bed and situates himself, flat on his back and stiff as a corpse, on the edge. This was a colossally stupid idea from every angle, no way is he going to get to sleep with them in the same room, much less in his bed. His eyes study a cobweb on his ceiling fan as he feels the bedsprings give when they slide in next to him. 

“You comfy?” they ask. He turns his head only to face them and they’re on their side, head resting on the inside of an outstretched arm. 

“yeah. ‘m good.” 

“You really sleep like that?” 

“...no.”

The silence between them is full of concern. It blares from every way they look at each other. 

“Sans. The point was for you to be more comfortable.”

He’s just staring, now. Oh god, they’re really here. They’re in bed together. Suddenly this is so very real and any notion of this waiting period being a precursor to a fizzle is gone. This is really happening. There’s no denying that any more. He’s still staring. Taking in the casual way they’re draped across his bed, like it’s nothing. The way they haven’t taken their eyes off him either. 

He looks back up at the ceiling fan. 

“...you’re actually here,” he mutters. “i called you in the middle of the night and you could’ve had waffles but you. came.”

“Come _oonn_. I didn’t come over to watch you not sleep. Just pretend I’m not here, okay?” They have to be fairly quiet, nobody wants an inquisitive brother awoken by voices. But Sans isn’t thinking about that, he’s busy noticing how close and hushed and _private_ their words are. He rolls onto his side, which happens to buff him along the bed a little closer to them. 

Their voice is so soft, almost as soft as the touches he so tangibly remembers.

“Is this better?”

“....yes.”

He knows how tired he looks, he’s seen it in the mirror a thousand times. He’s tired, he’s in a more comfortable position, he’s calmer than he was when he called. He should go to sleep, but his eyes are bright, taking in the sight of them, under the covers, sideways, cheek squished. Relaxed. With him.

They turn their cheek and bury their face in his pillow.

“Sans, please. You’ve gotta stop staring at me like that. You’re gonna make me break my streak. It’s been a whole week since my last, uhh, slip-up.”

He snickers at that. “fine.” He rolls over to his other side so he won’t bother them.

“Now go to sleep or… or I’ll touch you.”

His body jerks. “what. why the fuck would you say somethin’ like that, you wanna talk about breakin’ your streak, how’m i s’posed to- mmmf.”

They’ve put their palm flat on the back of his ribs and they’re rubbing it over his back, his spine, in slow, soothing circles. Their hand is warm and he feels all the tension leave his body.

“See? I warned you,” they say, teasing but still very quiet.

His eyes close all on their own and his mind is quieter than it’s been in a very long time. His last worry before he drifts off is that he’s drooling all over his pillow.

\- - -

When he wakes up, the pillow is soaked. He notices by rolling his face into it, blearily. He feels so sluggish. 

Then his body washes with chills as he remembers what went on the night before. He can hardly even believe it. They came over, they stayed. For him. Appropriate behaviour couldn’t matter less to him right now. He’s so happy. He’s grinning into the dampened pillow. He gets to wake up and they’re going to be the first thing he sees. 

He curls up on himself. Okay, he’s prepared. And then he hears loud footsteps, a bustle outside, and his door opening. 

“HELLO? BROTHER, I DON’T WANT YOU TO SLEEP IN SO MUCH YOU END UP LATE!”

He bolts upright. Fuck, _fuck_. He snaps his eyes open too quickly and has to rub them. 

“uh, papyrus, i-- i can, uh--”

When he can finally open his eyes, he sees his brother in the doorway, looking confused. He looks between Papyrus and his bed. His panic turns to something cold and hard. 

They’ve gone. 

He waves the situation off as having had a strange dream. Papyrus accepts it and leaves. He checks his phone for the time, and it’s later than he should be getting up - he was far more asleep than usual - then realises he doesn’t have a message from them. Nothing. 

They were here, right? Was there any evidence at all? He chuckles in spite of himself, because wasn’t that the same thing he’s been asking himself about this whole ‘relationship’ since it started?

He struggles with the idea of getting up, struggles with the idea of pretty much anything, completely unsure and lost in a sea of blankets. He wanted them to be here. He just wanted a moment of _something_ where he wasn’t out of his mind tired. And then he feels guilty. Was this too much? He should never have called them. How could he have even thought--

When he pulls on his blanket, something crinkles. A slip of paper. Left on his bed. He grabs it up. It’s folded neatly and written in green crayon, an implement he can actually see in its regular place on his floor. 

_‘Sans,_

_Would have texted you, but you didn’t want to leave anything incriminating. I hope waking up by yourself wasn’t too much of a shock. I just thought we’d get through this easier if we didn’t… if it was like this. You know._

_I don’t know how difficult it was for you, but it was for me. Seriously, this was the last thing I wanted to do. But it’s not much longer and then we can do this all the time, if you want to. I hope._

_Oh, and I know that being the one up first and getting to see you asleep gives me an unfair advantage. I do intend to make it up to you._

_X’_

He dresses as quickly as his tired movements will allow and stuffs the note in his pocket for safekeeping and future reference, for when the days ahead stretch out too far in front of him and he needs a tangible reminder. He even likes their handwriting, he notices. It suits them, even in green crayon. 

He busies himself with looking busy while his brother rushes around putting everything in order for the day. Sans is pouring himself a cup of coffee when he finds himself cornered by a somewhat manic-looking Papyrus. 

“YOU KNOW,” he starts, and Sans thinks maybe he does know, and doesn’t want this conversation to continue, “THIS MORNING I NOTICED SOMETHING VERY PECULIAR.” 

The cup of coffee steams in his face as he holds it there, frozen, the liquid just at the lip of the mug. 

“really, that’s cool.” 

“WHEN I WENT OUT FOR MY MORNING JOG, THERE WAS A NEW CAR IN OUR DRIVEWAY. AND WHEN I CAME BACK, IT WAS GONE. SANS?” 

“mmm?” It’s the world’s longest fake sip of coffee. 

“DID YOU SNEAK YOUR HUMAN IN AFTER I WENT TO BED?” 

“mmm.” He shrugs. 

“YOU KNOW YOU DON’T HAVE TO DO THAT. WE DON’T HAVE THOSE KINDS OF RULES HERE, YOU CAN, UM. YOU KNOW. UNLESS! THEY ARE TOO INTIMIDATED BY MY GREATNESS AND ARE NOT YET READY TO EXPERIENCE ALL OF THIS.” 

“that’s prob’ly it, then.” 

“IN THAT CASE, I UNDERSTAND. I… I DO HOPE I GET TO MEET THEM SOON, THOUGH?” 

“yeah, paps. pretty soon, i think.”

Papyrus gives him a look of understanding that makes his day of administering exams a little easier to shoulder.


	7. Heartstring Theory

**Notes for the Chapter:**

> Haha whoops, we ran out of pre-written chapters. 
> 
> Anyway, the response from youse guyse has been awesome! Y'all must've been thirsty for some Vitamin P. That stands for Professor, what'd you think it was?

He spends the weekend in front of the TV with Papyrus, half-paying attention while grading. It takes longer that way, but it’s easier to deal with. He’s caught up with most of his larger classes, including theirs, but he wants to finish so he has fewer distractions once the semester ends. Which, he’s not even sure how long they’re going to stick around. They haven’t discussed it at all. He selfishly hopes they stay close by for the break, or at least for a few days after the end of finals. He makes a mental note to ask them once they’ve said and done everything that needs to be said and done. 

Monday morning, 8:00 AM is the time scheduled for their section’s final. He’s not used to being up that early on a Monday, so he’s almost late, as usual. For the most part everyone’s in their seats and ready to go. A few stragglers trickle in after him, but he can’t really blame them. 

“k, folks, it’s time. hope ya studied.” 

He passes the test out to each row, watches each piece get handed down. 

“when you’re done, come get a course eval sheet. doesn’t have to be poetry, but at least pick some numbers. k, you’ve got a little less than 3 hours, but it prob’ly shouldn’t take all that. you can start, now, and may the mass times acceleration be with you.” 

He hops up on the table next to the podium and waits, messing with his phone. He’s a little sore about the fact that he couldn’t get a scantron machine this morning and he’ll have to wait to grade the tests. About an hour in, students start making their way to the front. One by one, taking their course evaluations and their tests, he bids them goodbye, saying stuff like, “hey, good luck kid,” or “‘s been fun. have a good break,” or “you’re a freshman, right? am i gonna see you in my 210 class next semester?” 

When _they_ come down to the front, they make a point to brush his fingers with theirs.

“I also have that extra credit assignment you said was due by the end of the semester, uhh, do you…?” 

He looks them dead in the eyes. It’s been so long and they’re so close. 

“i want it now.” 

He watches their face bloom. Yeah, that was worth it. He takes it from them and watches them go.

At home that evening, he has to flop onto the couch for a while and chill out, like usual. A skeleton only has so much energy. He flicks the tv on with the volume low and starts dozing off. Papyrus isn’t around. He’s grateful, very much so, for his brother not asking more curious questions after Thursday night. 

He remembers he intended to ask his human about their plans over break, but then, he can’t get onto something like that until they get… up to speed with each other. Still, he kind of wishes he knew if they had plans. For a ballpark of how long ‘getting up to speed’ might be.

Sans is nodding off when his phone rings. He digs it out of his pocket and swipes without looking. 

“nmn’llo?”

“Hey.”

Oh. Of course it’s them. The sound of their voice shocks him fully awake. 

“hey, uh. isn’t this a bit…”

“Eh. So I called your number, big deal. ‘S not more risky than you calling me at 1 in the morning.”

“guess so.”

There’s silence. The kind where you wait to see who cares enough to speak first.

“so is this where you ask me to drop by so i can help get you to sleep, or…”

They laugh, a proper, full laugh that makes him feel like he’s glowing. 

“I’m just saying hi! And hey, my final’s done, so. You know. We’re pretty close.”

“s’pose we are.”

“I don’t know about you, but I feel like this made me a lot more, ah, sure. About doing… about wanting to do this. Because it’s been about two months and um… you know.” He doesn’t say anything, but he does feel pretty proud of himself. “That was a nice one, pulling that line off,” their voice dims a bit, “before I left, right out in the open.”

He chuckles. It’s a low, private kind of laugh. 

Another brief, wordless interlude. 

“hey. i didn’t get around to thanking you for the other night. i’m glad ya were, uh… available. it was… pretty… cool.”

“Yeah. Heh. Glad I could help. Anytime, y’know. Although maybe in the future, you won’t have to call me up to get me over to help. If it happens again, I mean.”

Suddenly he could really use a drink. 

“uh-huh.” 

“Also, I meant what I said about having a bit of an advantage. I’m honestly sorry for running out. It sucked. But I woke up before you and you were all curled up against me and I knew for sure if you were awake too I wouldn’t manage to bring myself to leave. Well, not without, um…”

A shaky breath eases into the receiver. “....mmm?”

“...When I said I wanted to touch you, I meant a lot more than a back rub…”

He clears his throat.

“i uh, kinda assumed that. ‘s why i reacted the way i did.”

“I wasn’t gonna do anything,” they protest, “not really. I just wanted to. It wasn’t the right time for it, though, I could see that. Tomorrow, though, all bets are off.”

“tomorrow?” He asks, quiet now.

“Yeah. You’ll have our tests graded by then, won’t you? I mean, I’m hoping. And I’ll be done with my last final by 3:00, so…” they trail off. When he doesn’t reply, “And once I have my A in your class, I’ll uh, come find you and umm. Y’know, blow your mind or whatever.”

He starts coughing. 

“y’sound awfully sure of yourself.”

“Yeah, well. I studied for you. _Hard_.”

He goes into his room and shuts the door, as that has become probably the only appropriate venue for this conversation. The movement itself is an admission of sorts, but he’ll make an effort anyway.

“then i’m sure you’ll get that a. uhh, i should probably get back to grading ‘n shit, but-”

“Okay. Can you give me a minute here, though? I’ve wanted to talk since Thursday and we haven’t gotten to… and I thought it was a bad idea to call when I should’ve been studying.”

The only place to sit here is on the edge of his bed, so he leans but tries not to put his whole weight there, just because. He’d hate for them to know he was sitting on his bed.

“sure.”

“This’s been so weird, right?” They laugh. It’s not fake, but it’s a little strained. “I mean, after all this. Don’t you sometimes think it’s strange? I know having time to think about it was a good idea, it’s not that. But I forget that you’re-- _were_ my teacher. And that being human is different from you, and… it’s just. Really, we’re just two people. That like each other.” A long pause. “Right?”

“right.”

He was so quick to assure them after the question, he barely realised what this had come down to. Thank god they’re not here to see him sweating.

“That morning when I got to wake up with you, I felt so… lucky. Oh god, you were so cute. I could barely keep my eyes off you long enough to write the note down,” Sans gives up and puts more of his weight on the bed. It creaks and he winces. “And that whole day, all I could think about was what would’ve happened if I hadn’t left.”

“mm. i thought, uh, for a second… i must’ve just dreamed it.”

“Aw, Sans! No, I’m sorry…”

They trail off. He can hear their shallow breathing down the line.

“..but i don’t really have dreams like that.”

More silence. He’s anxious, they sound like they’re stumbling, too.

“if. if you’d stayed that morning…” his voice has gone self-consciously quiet, even though he’s the only one home. He hears a shuffle from their end and remembers them saying they’ve recorded his voice multiple times. “what were you. gonna do.”

“Umm… it would’ve been such a bad idea. Wrapped you in close until you woke up. Worse idea? Nuzzle on you if I got impatient. ....Worst idea? Kiss your neck…”

Sans chokes softly, and he knows they heard it. His breaths keep catching in his throat. Even obvious as it’s been that this conversation was a blatant bid to go in this direction, actually hearing this stuff said aloud is catching him off-guard. 

“you. uh. you want me that bad.”

“Y… yeah. I seriously can’t wait to get my mouth on you again. It’s been killing me that I can't.”

Okay, he can remain reasonable about this. He can keep a clear head. They can’t see him, they just wanted to talk about this to make it easier, he can deal. He can. 

“Sans…” they groan. “I need you so fucking bad.”

All his bones flush hot. His hearing is oversensitive from straining to pick up everything over the phone. He feels himself getting hard, and hears it too, as his pants strain to contain the glowing erection that just summoned itself at their words. 

“fuck…” he breathes.

“Shit, I know we decided it’s wrong until tomorrow. But I wanted you to know anyway. Even if we can’t. Because if it wasn’t _forbidden_ I’d be on my way over there right now. And next time, I’m not leaving your bed until I’ve been on top of you first.”

“...” He turns his face away from the receiver a little. “c’mon. you’re kiddin’ me here.”

“Please tell me it’s the same for you?”

Shit, shit, shit.

“yeah. yeah, it’s. i want. ...it’s the same.” He’s not fucking good at this.

They breathe a sigh of a laugh on the end of the line. “Good, I… I sometimes can't tell with you. You make me so nervous, I just… I tie myself up in knots hoping you want me half as much as I want you. You've been so, I dunno, _moral_ about this whole thing, a lesser person might think you weren't really that interested? I can tell you right now I haven't been as virtuous.”

“virtue’s got nothin’ to do with it. ‘s pragmatism that’s been holding me back. i…” he works his jaw, trying to make the words fall out. “want you. i can’t, uh. i can't just turn somethin’ like that off.”

They exhale, but it catches on something akin to a whimper. “Say it again?”

“which part?”

“You know which part.”

What, once wasn't enough? “i want you. so fuckin’ bad.” Evidently not, even for him, as the repetition undoes another layer of his reserve. Or maybe it's the moan he receives from doing so. He mops sweat off his forehead but it does nothing to cool him down. 

“you’ve no idea how close i’ve been this whole time, how bad i sometimes wanted to just say fuck it an’ show ya how you make me feel.” His eyes are shut tight as he says this, as though the words are being painfully extracted from a deep cut. 

“I would've liked that. Would’ve made it easier on me. I was so nervous, that time in your office. I think… I'm glad you stopped me, but there was so much more I would’ve done.”

“oh. yeah. i got that.” He aims to rest his arm on his leg, but it’s way too near the area that’s throbbing for attention. He lets his fingers drape between his legs and doesn’t manage to muffle the grunt he makes. “i uh, got that… pretty clearly. but, look. i didn’t wanna go that quick, not there in my office like that, when the whole point…” it’s coming out gruffly between gritted teeth, now, words spilling out faster the more hazed over his mind becomes. “the point is that i fuckin’. like you. a lot. an’ i don’t wanna fuck this up.”

“Sans--” they gasp. “I like you-- a lot-- so much. So, ah… in the spirit of holding off to not f-fuck up, I’m…” there’s still part of him that makes him assume he’s not really hearing what he’s hearing. “I’m, uhm, gonna have to go. But I think you know why. L-let me know if you wanna m-meet up tomorrow. Anytime. Shit, I’ll-- mn-- see ya.”

When the connection clicks, he’s actually partly relieved, but undoubtedly more frustrated than he’s ever been in his life.

He takes a few stabilizing breaths, then sends them a text: _yeah. should have your final grade entered tomorrow before 3._

He's not expecting a response at all, necessarily, but certainly not one right away. They're busy. He wants to join them, badly, but their parting words did little to reassure him, as did his seeming inability to control his own responses.

How do they do that to him? They always get it out of him, it's not safe, it's not good to be like that. His own personal history, everything in his past, points to that conclusion. But they're going to get everything out of him, eventually. He's going to say too much too soon and they're going to feel stuck with him and…

And that's the last thing he wants, is for them to feel stuck with someone they shouldn't have even been with in the first place. But he knows he'd confess anything to them. Stuff he wouldn't - isn't _capable_ of telling anyone else, they'd draw it from him like poison from a puncture. And they would see him more clearly, and they would care, and they would stay. He thinks so, anyway, if he knows them at all. 

He can’t do that to them.

Maybe this was all a mistake. How could it be anything else? He's their fucking teacher. He won't be, soon enough, but still, so much happened while he was. He's a jerk, an idiot if he thinks that didn't color any of their past interactions.

The more he thinks about it, the more sober he becomes and the jarring rift between his current train of thought and _what he knows they’re doing right now_ widens. Maybe he should stop thinking about it, but it’s hard not to be acutely aware of what someone, out there somewhere, is doing to the thought of him right now. 

And it chills him. 

The idea of waiting was to stay clear of this kind of guilt. Sans idly taps his thumb on his phone’s screen. Waiting didn’t quite pan out. Hell, they’ve been in his fucking bed already. But going back to that memory reminds him of the touch they administered without being asked, something so private and gentle he’s never known anything quite like it. That morning he woke up and didn’t feel what he’s used to feeling because he thought they’d be there beside him. 

He fishes in his pocket and brings out their note. The crayon’s a bit smudged. He frowns because he still can’t help feeling happy about the sentiment as his beady eyes flick across each secretive word. 

He remembers when they took his hand under the table at the coffee place. 

He still wants that. More than he can put words to.

But addressing this in any sense would require talking about these things, and he remembers the dirty things he tried to just say on the phone - they were true enough, and he shudders slightly - grinding those out through gritted teeth would be only a fraction as difficult as talking about how he feels. Asking for--

The front door shutting sounds absurdly loud and makes him jump. It takes him out of his reverie, at least. 

“I’M BACK, SANS. YOU DON’T HAVE TO COME OUT BUT IF YOU DO, I GOT YOU MARSHMALLOWS.”

Marshmallows are nice. They're not usually nice enough to tempt him out of his room when he doesn't want to come out, but for now it's a welcome enough distraction. 

Well, he’ll come out when he’s decent, anyway. That takes some effort on his part. But Papyrus is home. With marshmallows. That's a boner killer right there. It only takes him a minute or two to get to the point he's comfortable leaving his room. 

The bag of marshmallows smacks him in the face as he enters the kitchen. He doesn't bother trying to catch it. 

“YOU'VE BEEN WORKING SO HARD LATELY, I THOUGHT WITH YOUR LAST DAY OF EXAMS COMING UP TOMORROW, WE'RE DUE FOR A CELEBRATORY MARSHMALLOWS ROASTING! ALSO! I HEAR TRULY _GREAT_ COMEDIANS SOMETIMES HAVE COMEDY ROASTS! I THOUGHT MAYBE IF WE HAVE ENOUGH MARSHMALLOWS LEFT, WE COULD INVITE ALL OF OUR FRIENDS OVER and your human AND WE COULD ROAST MARSHMALLOWS _AND_ COMEDY ALL AT ONCE! TOMORROW!”

_Tomorrow_? 

Well, shit. Now he kind of wishes he'd stayed in his room with his sad boner. 

When Sans doesn't reply, Papyrus shrinks down a bit, not quite to Sans's height, but close. 

“LIKE A PARTY. FOR YOU, SANS. FOR MAKING IT TO THE END OF THE SEMESTER WITHOUT ANYTHING AWFUL HAPPENING. SANS?”

God, he's touched. Papyrus clearly has no idea what a roast actually entails or he would never have suggested it, but it's the thought that counts. But why'd it have to be _tomorrow_? And _why_ did he have to phrase it like that.

“uh. i. uh. i have to think about it, i’m probably gonna be pretty tired.”

He's garbage. Anyone that can make Papyrus look like that is garbage.

“BUT. YOU'RE ALWAYS TIRED. HOW CAN YOU EVEN KNOW YOU’LL BE EXTRA TIRED TOMORROW? I DON'T. I DON'T UNDERSTAND, I THOUGHT YOU'D LIKE IT.”

For god’s sake, do something.

“you didn't let me finish, uh. i’m probably gonna be pretty tired so you'll have to do all the work.”

Papyrus nearly - _nearly_ slumps over in relief. 

“OH! WELL OF COURSE. I WAS GOING TO. WHAT TIME DO YOU THINK YOU'LL BE GETTING HOME?”

“uh. probably pretty late. like seven, maybe.”

That should give him enough time. If it goes well, if it blows up in his face. Either way. It’ll come and go whether he’s ready or not.


	8. Equilibrium

**Notes for the Chapter:**

> *audible wink*

The next morning he has one exam left to give and it's from eight to eleven. He takes an hour for lunch, runs two sections’ answer sheets through the scantron and has all his lower levels’ grades entered by two. They got their A and they’re going to hear it from him, first.

He wastes the final hour in his office in a haze of meticulous worry. It’s a long enough hour that he has time to be proud, too. For what it’s worth, they did turn around from almost dropping his class to getting an A and they honestly worked for it - unconventional methods notwithstanding - and he’s proud of them. He really is. If he squints he can pretend his teaching abilities had something to do with it.

“Hey!”

He freezes. He hadn’t heard their approach. Turning to them, they’re none-too-neatly framed in his doorway, and he can see they’re breathing hard. Had they _run_? He can’t pretend to understand that impulse.

Oh, he’s glad to see them. He is, no matter what, he just wishes he knew what to do. What comes next.

“hey. uh. you got an a,” he says after a moment of taking the sight of them in. That probably wasn’t the right thing to say, but oh, well. Business first. “so y’know. good job.”

They’re still catching their breath and getting excited at the same time. “I did? Hell yeah, I knew it!”

Sans just sits there with his hands fumbling. They’re so happy and flushed and panting and it’s a good thing his default expression is a smile because he doesn’t really remember how to do one properly.

“So, I mean. That’s it then,” they rock on their heels. “Weeee made it.”

“yeah, guess we did.”

He’s not sure what to say. He keeps just looking them over, trying to find something different about them.

“welp, i’m free for a bit and i don’t think we can, uh, celebrate on campus. let’s just…”

He hops up, gathers his things, and ushers them back from the door. He walks backwards away from them, motioning for them to follow along.

They skip to catch up to him, grinning.

“Celebrate, huh? We going to your place?”

He jams his hands down in his pockets where he can ball them up into tight fists so they can't see how on-edge he is.

“actually we can't go to mine cuz i uh, sorta told my brother i wouldn't be home ‘till 7.”

They bark out a laugh. “Geez, _okay_ , you're makin’ me blush already and we're not even out of the building yet. But that's fine, we can go to mine.”

Somehow, that's worse. He resists the urge to wring his hands together, to visibly fidget in front of them. He doesn't want them to think… maybe that's just it, he doesn't want them to think. About him, about this situation. If he could just call it off and not worry about the conclusions they might draw from that, if he could just put this off long enough to get himself figured out. Goddamn, he needs help.

“Oh my god. Except. Oh, fuck me, I'm so dumb, I can't believe this-”

“what? what's wrong?” He jumps on the possibility of interruption perhaps too quickly.

“This is so embarrassing, I can't believe I forgot… I'm out of toilet paper at my apartment and…  um… yeah. I'm not…”

“then let’s go get you some tp.”

They relax a bit. “Shoulda known you'd be this cool about it. I promise it won't take long. In and out, I swear, then we can, um. Celebrate.”

He chuckles and he sounds surprisingly at ease. “‘course. not like i know what you humans do with the stuff.”

That gets him a bigger laugh and they pretend to take him seriously as they walk together. He gets some choice explanations, each more elaborate than the last.

Sans eventually finds himself grocery shopping with the human. It hits him like that. One second everything was normal, back in a place of education with the usual faces around him. Now he’s shuffling past an array of cauliflower with nothing familiar to look at, especially in monster terms. Even the level of indoor brightness seems unreal.

“Okay, over here. Sorry, I’ll only be a second--” they say, but they’re almost immediately distracted by needing a new pen and some soap. And then they pause at a magazine rack. He watches them with vague amusement.

“i guess i could, uh. well. since i’m here, papyrus might want me t’...”

He could do something to help supply the party. But now he’s remembered the party. He trails off and wordlessly follows them into the next aisle, staring at the floor.

They load up their arms with the items they came for and a few they didn't. Then they're having trouble carrying it all, so they wander back toward the front of the store for a basket.

“y’sure ya don't wanna just get one of those carts?”

“Hmm? Nah, I'm almost done, I think. Actually, shit, I'm out of fish flakes. Fuck it though, that can wait…”

“hey, don’t flake out on your fish on my account.”

They pause, give him a weird smile, cocking their head to the side.

“Huh. To the pet supplies aisle?”

He nods and they make their way back across the store. If they notice he’s dragging his feet, literally, they don't say anything about it.

They reach up and grab a little cylindrical bottle with a satisfying rattle sound.

They look at the label and grin, suddenly.

“Hey, why did the two fish never have sex?” they ask.

He glances around involuntarily.

“what? no. i mean. why?”

“Because they were in a planktonic relationship.” Sans blinks twice and stares, not a twitch. “Uhm… Sans? You doing okay?”

“I…” Nothing comes out. He can’t even answer, the only thing he’s sure of is not wanting them to know. “uh, yeah. i.. no, i’m good. yeah. who’s, uhh… why d’you ask…”

“Hey. Don’t worry. I’m done, so… no more stalling.” They come closer to him, their arm cupping him effortlessly around the shoulder. “Maybe we can start getting better acquainted…”

This is happening. In public.

“Sans?”

He looks at the neatly lined packets of dog food.

“Sans, hey. Hey. Please say something.”

“i’m sorry, my mind is drawing a plank… ton.”

They straighten, worrying their bottom lip in an expression he’s coming to recognize as their serious face.

“It seems like you’re a million miles away,” they nudge him.

“i just don’t think i can do this right now,” spills out of him before he can really check himself. “uhh. it’s not. i haven’t-- uhh--”

He scrapes his hand down his neck vertebrae and clavicle. They don’t deserve to have this done to them. He needs to talk but every word that comes to mind would sound dismissive or wrong. They really did wait for him all this time and now he’s going to fuck it up--

He’s brought out of paralysis by their hands clasping his shoulders. They look serious. So serious they’re not chewing their lip or anything. Scanning his face. Worried. He’s made them worried. He never likes doing confrontations but isn’t usually bad at it--

“it’s not like i’ve changed my mind or anything.” He doesn’t know what to do with his hands, letting them dangle uselessly as they stare him down. “kid, you slowed way down for me. everything you do is fast, but you’ve been…  well, i mean, thanks for waiting for me to catch up, but…”

They tilt their head. “What’s fast?”

“maybe it sounds weird after putting it on hold for a couple months, but i’m not there, yet. i’m... i’m sorry? it’s not you, i still want this stuff, but i’m still seven kinds’a hung up on whether this is wrong or not, even though we did everything- well, most things right...” His jaw is clenching up.

They lower the basket gently to the floor and he sees them reach for him, but hesitate and stay at a respectable distance, angled side-to-side with him, and they take his hand. He shudders at the warm flesh on his fingers. With a very slight motion they brush soft sweeps against his bones with their thumb.

“It’s okay,” they look right into his eyes to say this. “I'm glad you told me. I should have guessed, I know you take your job seriously and… I’m not going to beg off because you won’t jump into bed with me right this second.”

Well, when they put it like that.

“In fact,” his hand comes up with theirs, intertwined, “I wouldn’t call it off if you decide you _never_ wanted that. It’s… you. It’s just you, okay. Have I been too pushy? I know I can be. At first I thought you had, y’know, just normal jitters, but… if it's more than that, I'm not going to push anymore.”

His jaw gapes, not unlike a fish, he thinks. Now his mind really is drawing a plank. A blank.

“I keep assuming we're on the same page about… well, everything, really. But that's why we have to talk about this stuff. And you know what they say about assuming…”

“yeah. it makes an ass emu.”

They snort.

“what, do they not have those up here?”

“Look, I'm serious. I didn't wait seven weeks just to get rid of some sexual tension. I like you too much for that, and if you still have reservations, I can wait some more while you work on them. All I want is to be kept in the loop. And maybe gross couple-y privileges.”

His toe taps in quick syncopated rhythm on the dirty linoleum.

“yeah. i can, uh. i can work with that. i just didn't want you to think that i didn't want-because i do, i really do, i just... my head is all over the place and i don't know what's good or right and i have to be sure, y’know? i need to be sure.”

They nod solemnly as they lean in to speak to him in a low voice.

“That’s good. Because when- whoops, no. _If_ we fuck, it's going to be because you’ve _shown_ me how sure you are.”

Then they pop up like a daisy, as if they hadn't just insinuated they’re going to make him beg for it.

Well, that's... one way to do it.

“Hmm. I think I'm ready to check out, now. Wanna watch a movie or something?”

“oh, right, ah-- see, remember how i said i told my bro i wouldn’t be home ‘til 7? well actually that’s ‘cause. he’s plannin’ somethin’ and…” he feels more at ease, he really does. A semblance of flow starts coming back to his hands, moving as he talks. “i think a few people are comin’ and he said you can come. if you wanna. if you wanna hang out with some monsters and meet my bro.”

They were picking up their shopping basket but nearly drop it. He takes it as shock before seeing the stars in their eyes.

“Meet your brother?! Oh my god, awesome! You’ve only been going on about him to everyone I’ve seen you talk to, for as long as I remember. And a bunch of cool monsters too? See, this’s what I meant by couple-y privileges.”

“you mighta seen him before. we’re pretty much the only couple’a skeletons in any given location. he came to that campus fusion studio opening a few months back. but you n’ I were just kinda. busy.”

“Is he as cute as you are? Wait, don’t answer that. I have to see for myself.”

They continue talking about how enthusiastic they are all the way through the till. Sans realises while watching them pay that his grin is natural again and it feels fitting. He’s loosened, like a knot that had gradually worsened itself finally going lax. He cricks his neck, too.

“Didn’t you say once that he made a suit of armour party costume and then never took it off?”

“yup. that wasn’t long before we got through the barrier. he’s still wearin’ it, i think. unless this party is finally time to wear a new costume.”

“Is it that kind of party?” they ask.

“nah. wouldn't mind seein’ you in costume, though.”

They give him a half-hearted shove and he makes a show of stumbling to the side. He’s incapacitated, so he can’t be expected to pick up any shopping bags.

“I think that's the first time you've actually hit on me,” they muse. “Not counting the, uh. The phone conversation from yesterday.”

“probably more like second but, who’s counting?”

“Me, I'm counting,” they say, sounding as giddy as he feels. “Man, that must have really been bothering you. Feels like I'm finally getting to see another side of you.”

He winces at the first statement and decides to ignore it.

“yeah? what’s the verdict?”

“It’s too soon to say for sure, but I'd say charming. Irritatingly so.”

“hehh. and it's only 4:00. wait ‘till i get goin’.”

“Don't make me regret saying that, please.”

When they arrive at their apartment, they take a moment to put away their groceries while he stands back and watches. They didn't buy much and he doesn't really know where anything is, so he waits for them to finish.

“Hey! Wanna meet my fish?”

“uhh. what?”

“Well, I mean. They won't say hi back, or anything, but.”

“ok.”

He follows along and restricts himself from making snap judgements about what he might see in their room. They gesture to the big, bubbly tank and he waves to the wiggling black bug-eyed occupant.

“i got a friend that's a fish. well, monster. you’ll meet her, tonight, actually.”

“That is bonkers. I'm so excited.”

They head back downstairs and set up a movie while they discuss the upcoming party and which of Sans’s friends they’ll be meeting. He falls asleep maybe ten minutes into the movie, and they let him, only waking him up when the credits are rolling.

It's dark outside and they haven't bothered to turn on the lights, either, but the first thing he sees when he opens his eyes is their face.

“Goddamn, you're cute. But we should probably get going or we’ll be late for the party.”

“nnrggmmmmwere y’ watchin’ me sleep.”

“Yeah. Sort of-- yeah.”

“ok.”

He shuffles to rearrange himself post-nap and get his sweater on straight. His teaching clothes still feel silly and of course he hasn’t had time to change. Then he realises they’re still watching him and he tries not to look self-conscious.

It’s very quiet. He makes a show of getting up. It’s dark and he’s at their place and they haven’t really done anything yet at all but he’s very aware they’d want to and _he_ wants to - he tries to shed it from his mind.

“ya like doin’ that? how long did ya stay over that morning and watch me bein’ dead to the world.”

“Oh, uhh. Not that long.” They consider the memory for a second, glancing upward. They seem to be gauging whether they can spin the actual amount of time nonchalantly and eventually just shrug. “Sorry. You have no idea how cute you are when you sleep.”

“you got me there.”

He tries not to dwell on the compliment, he’s not even sure whether he likes it, but it definitely can’t lead them into a conversation of _that_ calibre right now. He stretches out and clicks four or five joints at once.

“C’mon then, lazybones. We have a _shindig_ to get to, haha.” They’re putting their coat on. “How many times’ve you heard ‘lazybones’?”

“about fourteen million.”

“And yet it’s still funny, right? Talk about mileage. And, talking about mileage, I’ll drive us over to your place, ‘kay?”

He isn’t sure whether it’s the nap or the situation that has him a little dazed. He’s getting into the passenger seat, clipping the seatbelt on, and trying to look comfortable even though it’s set much too high on his body.

He almost gives directions, then remembers he doesn’t have to.

He feels like he's forgetting something as he follows them up to the door, but maybe it's just the total unfamiliarity of the situation. He's never had anyone to bring home and introduce. It's… surprisingly mundane. Not that he isn't a bit jittery about it; he has _no_ idea what to even introduce them as and he's not even sure he wants anyone to know they were his student until a matter of hours ago. But their steps are confident, their smile easy,  as they turn to wait for him to catch up. He's not as worried as he might have been. This just feels like a _thing_ that people do.

Still, though. It’s not everyday he gets to do this, and he’ll never get to do it again for the first time. Oh, man, Papyrus is gonna… actually, he has no idea what Papyrus is going to do. He rarely ever does.

They reach up to ring the doorbell and he stops them.

“wait, i… i have an idea.”

“I'm listening.”

“um, so, my brother’s been dyin’ to meet you since… uhh… well, for a while and i just think it’ll be funny if, uh. well, we have this old gag bit we do sometimes, it's dumb but he humors me and. uh anyway, just um. wait here and i guess just... be prepared.”

“Prepared? Prepared for what, should I be worried?”

“heh. nah. i mean, probably not. he's not dangerous, even if... well, you'll see.”

And with that, he slips inside.

“OH! IT'S JUST AFTER SEVEN, THAT MUST BE SANS AND--” Papyrus rounds the corner. “NOBODY ELSE AT ALL. THAT’S FINE.”

“good thing we're used to havin’ no bodies, then, huh?”

“THEY DON'T GET BETTER THE MORE YOU USE THEM.” Papyrus turns to go back into the living room.

“wait, wait, i have a favor i gotta ask.”

Sans beckons his brother back over to the entryway and whispers his plan.

“UGH, THAT OLD THING? WHY NOW?”

“just… trust me. start it off.”

Papyrus clears his throat and begins in a voice devoid of his natural inflection, but at least 30 percent more volume: “SANS. OH MY GOD. IS THAT.”

That’s what you get when your voice coach is a literal robot.

He has to cover his mouth but can't hide the shaking of his shoulders as he watches the realization set in.

“A HUMAN???!!?? SANS!!! SANS!?”

Papyrus is buzzing like a computer model of a molecule in a solid.

“uhh, actually, i think that's our front door…”

“OH!!! NOW SAY IT! SAY YOUR LINE!! SANS, I SWEAR TO GOD IF THIS IS A PRANK-”

“hey, what's that behind the d-”

Sans barely gets out of the way in time to avoid being crushed by the door.

“HUMAN!!!!!”

The door bangs, there’s a shuffley commotion and it’s too chaotic to tell who is what, but Papyrus soon stops yelling and he pulls said human into their home. He has to give credit where it's due, they’re better prepared for that than he expected they'd be.

“so uh, this’s my brother, Papyrus. he’d tell ya he’s glad to meet you if he could do words right now.”

If they’re going to be meeting the whole gang tonight they can’t be too overwhelmed by just Papyrus… but they’re laughing. A lot. And Papyrus is beaming at them-- pretty much his usual expression.

“You guys are _dorks_. Oh my god.”

They smarten themselves up after that initial flurry of introduction, then there’s a moment where it looks like they’re sizing themselves up against Papyrus, who as usual, is a good bit taller. Then they hop up in place and give him a goofy-sounding smooch on the cheek.

Papyrus squeaks.

“Okay, one down,” Sans’s human winks at him. “And I was promised a whole _party_ full of monsters.”

They’re already inching towards the living room and peeking into each corner inquisitively.

“IS… DO THEY NEED TO KISS _EVERYBODY_?”

Sans hasn’t moved.

Oh boy.


	9. Inelastic Collisions

**Notes for the Chapter:**

> Oh, hello.
> 
> It's uh, been a while. You're looking well.
> 
> We've had some changes, too. LIKE THIS!!!!!!
> 
>  
> 
> [Sweaty sweater-vested Prof. Sans and bescarfed Student being CUTE](http://artanddetermination.tumblr.com/post/143583263762/stranger-than-friction-by-auntie-diluvian-and)
> 
>  
> 
> [oh hot damn y'all it's THE SCENE from chapter 3 you've got your hands all over him holy shit](http://bittersweetdeath.tumblr.com/post/143924762783/fekjalfjklajfkea-fanart-of-chapter-3-of-stranger)
> 
>  
> 
> ok that's all we've got for now. Thanks for your patience, the people will sing of it for ages to come.

Sans’s closely guarded little secret is flitting around the room, between his strongest friends and a few monsters he only vaguely knows. And as he watches, expecting a blip or hesitation, there isn’t one at all. Waving, excited nodding, and - he can’t believe they were serious - giving some of them enthusiastic greeting kisses.

He stands there in the doorway not knowing where to place himself.

Sans watches that cat guy - what was his name, he’s ordered fast food from him at some point, burger something-- Burgerpants - stumble forward to be introduced and get in on the action. A sudden panic hits him when he realises they didn’t have a discussion on whether he and them were, well, formally together or not. He braces himself while listening and hears “here with Sans” - a not too revealing and perfectly truthful response. He reminds himself to breathe. Papyrus has come in next to him and he doesn’t want his brother noticing the jitters after he did all this just--

Sans wasn’t expecting to get bowled over by something blue.

“Sans, what the _fuck_.”

“hey to you, too, undyne. how’s th-”

“No, I mean, seriously, what the fuck,” she hisses a second time.

He stares back at her, dumbfounded.

“I mean, shit, man, I never would have thought-” she's gesturing, nearly throat-punching a guy, as one does, and he follows the general direction of her movements across the room… oh.

“Never would have pegged you to be the kind of guy who brings home a fucking…”

He’s scanning the room for exit paths, but it's his own home so all he knows is exactly how well she's cornered him.

“You know what? I don't even have the adequate words to describe just how crazy, stupid...”

He can't speak, he can barely see straight, but at least he’s prepared for the worst. 

“...ridiculously far out of your league they are. How in the hell did you pull that off?”

He cracks a grin he thinks looks smug and laughs in a way he hopes doesn't sound as relieved as he is.

She doubles over, cackling at him.

“Hooo, oh my god, Sans! You’re sweating buckets! Ho shit, you thought I was gonna slam you for dating a human, right? Man, I got you good! Hey, seriously, though: don't mess it up.”

He doesn't even bother to point out that he's not officially dating them, and she’s already gone, anyway, ostensibly to give Alphys the play-by-play. Whatever they’re saying out there, it’s clear everyone will know he’s involved in this and as such he really doesn’t need to be nearby. Sans breaks off for the kitchen. He has a feeling he’ll need a drink. 

What do they have, anyway? He shouldn’t - really shouldn’t - be having anything that’ll impair his senses. He finds a big punch bowl in the kitchen and goes to dunk a cup straight into it, downing a huge gulp like it’s a shot. He definitely doesn’t want to be around with all the introductions taking place. He can imagine quite well the way everyone’s eyes would slide over to him every time he gets mentioned.

Two minutes later and Burgerpants (hell, he can’t remember the kid’s actual name at this point) has swanned in and is leaning on the counter next to him and trying to get some sort of information out of him.

“So like. How’d you do it, man. How do you get in there with those types?”

God, every person here must want to see him sweat.

“types? humans?”

“Nah, just _hot people_! Human, monster, whatever. If y’can’t trust a hot monster then surely you can’t be trusting a hot human, am I right? Hell, I wouldn’t even know where I stand with a human.”

“well, there’s one right here. why don’tcha get to know ‘em.”

Oh good, now the guy’s tail is twitching and _he_ ’s sweating.

“Uhh, maybe. I mean, I haven’t talked to many of ‘em. I mean. Maybe I will!”

Sans chuckles and decides to get back in there with them, in case anything important happens. He might as well face it head-on.

He ladles out another cup of punch, a decent enough reason to get close to them without seeming clingy.

They've migrated towards the back door and are being interrogated by Bratty and Catty while Alphys stands by, cowed somewhat by the exuberance of the other two.

“Wait, woah, you're here with _Sans_ Sans?”

“Yeah! And are you here _with_ him or are you _with him_ , with him?”

“Oh my god, Catty, is that rude? We’re so rude!”

To their credit, this is the first time they’ve looked truly confused, as far as he’s seen.

“Um, yes to all, I think?”

Well, that's that. Bratty and Catty exchange a glance and a bizarre, elaborate handshake that devolves into unchoreographed, gleeful arm-swatting when he sidles up and passes them the other cup of punch.

It's him that nearly does a spit-take, though, when Alphys asks how they met, but his brief moment of panic is unnecessary. They're composed, as clearly this is not the first time they've had to answer that question.

“He, um. He talked me out of what would have been a bad decision.”

He can't put his finger on why, exactly, but that response staggers him so much that the ensuing soprano chorus of aww (which he's not convinced the situation entirely merits), as well as Asgore's pronouncement that he's managed to get the fire going outside, are tuned out as background noise. As the bulk of the rest of the guests head outside, he steals his particular guest away from the group.

“Your friends are kind of awesome,” they say, musing over their punch.

“heh, yeah, this is a pretty good bunch. so uh, i was thinkin’, maybe we'd better get our story straight, y’know?”

“Oh! Yeah, I- whoops, uh, was what I said- was that okay or should I not have-”

He attempts to placate them. “no, no that was- it was, uh. nice. clever. although, i mean, not exactly how we met, right?”

They laugh. It's loud and clear with half the room having wandered outside, and it's just for him.

“Yeah, I guess we met a little before. That was just when I realized I had a huge crush on my physics professor.”

“yeah? that what does it for ya? ‘no, don't go to plants and people, i’m sorry i was a colossal dick...’”

“Just about. So, what should we say if pressed for details?”

He twists his face in thought.

“I’d… really rather not lie, but it's up to you, since you're the one who'd be under scrutiny, really…”

“yeah, i wouldn't wanna ask you to lie, though, and honestly i don't wanna do that either. so i guess we'll just…. _fuck_. we gotta tell ‘em the truth, don't we? _fuck_.”

They loop their arm in his to lead him outside.

“It'll be okay. I doubt this will change anyone's opinion of you. Not with the version _I_ plan to tell, anyway.”

Their words don’t really seep in, given how he’s focused on how naturally their arm joined up with his to guide him forward. It might not look like it, but they _are_ leading him. He’s just making it look like he’s not hopping to keep up.

“Hmm…” they mutter, only just quiet enough as they near the rest of the group. “So, colossal dick, eh?”

Sans physically stumbles and tries to recover himself. A few eyes wander his way as he gets back in stride. He can only hope the low lighting covers his bright blue cheeks from them. He clears his throat pointedly and shoots his human an offended look when they laugh.

“Oh, c’mon! Seriously. I know. Skeleton. No expectations at all. Promise. None. The bar’s so low, even you might just walk into it.”

Why can he never think of any comebacks when they needle him like this.

The monster group looks as cosy as can be. He veers off to greet a few of those he hadn’t managed to bump into yet, a few old Grillby’s regulars. The bunny monsters look particularly warm and fluffy out by the fire, picturesque even. He holds a fist out and they bump it, his old barmates all speaking over each other with casual blessings. It looks like the fire itself is changing colours behind them. Asgore is still tending it, taking up a whole quarter of the surrounding circle by himself. Whatever he’s doing has the clearly magical flames going through a constant rainbow like kitschy fairy lights.

Sans looks back at his human and watches them zip their jacket up, then extend their hands toward the fire, while glowing in bright rainbow swatches.

He stares because they’re here. In the middle of this. In his life. Among practically everyone he knows. And they get closer to the fire, ahead of him, and take up a free seat on a big log beside Undyne. The two bump shoulders, they point at him, and he approaches, watching them laugh.

He is so boned.

There's nothing he can do but sit next to them, eat s’mores, and hope they don't realize just how much.

Evidently, at some point, someone had explained to Papyrus just what a roast entails, and to Sans’s far right, he’s having a spirited argument with Undyne over his subsequent veto of the activity.

“Aw, come on, man! I came prepared with a whole arsenal of insults to hurl at Sans and now you're telling me I can't use ‘em?”

“I FAIL TO SEE HOW THAT'S ANY DIFFERENT FROM HOW YOU NORMALLY PREPARE FOR ANYTHING, EVER, BUT YES, THAT IS WHAT I AM TELLING YOU.”

“ _Lame_. Give me one good reason why.” She gives him a ‘playful’ shove that would most likely send anyone else into the dirt, but Papyrus, entirely unfazed, launches into a thorough explanation.

“A, BECAUSE IT'S RUDE, B, BECAUSE I DON'T THINK MEANNESS IS GOOD COMEDY, C, BECAUSE I'M RIGHT AND YOU KNOW IT, D, BECAUSE HE'S HAD A ROUGH YEAR SO FAR, E, BECAUSE I SAID SO, F, BECAUSE…”

His human’s gaze had been wandering, their focus on listening to some of the other monsters’ conversations despite the din of the one going on right next to them, but at the mention of Sans’s ‘rough year’, their fingers tangle with his and they lean into his shoulder.

 _Sorry_ , they mouth to him.

“what for?”

“I think I'm part of that? Why you've had--”

“no. no. you-- no. shut up.”

He wraps an arm around their shoulders and holds them close. He stays quite still like this for a while until their arms drift around his midsection too.

“Well gee, how CUTE,” Undyne yells from somewhere to his left. “Are you cherishing your skeleton?!?”

“Um,” he lets his human free as they fluster under all the attention. “I… I guess?”

“Good!”

The group gets caught up watching Asgore hand around a marshmallow bag, individually taking one or two as it comes their way.

“Are you okay?”

Sans did wonder if they were going to press the matter. He has his jaw set, again searching for their hand and holding it. When he catches that sense of determination from them again - in their eyes, in the way they’re looking at him - he takes an extra moment to answer.

“believe me. it’s fine.”

He clears his throat and taps on Papyrus’s elbow.

“hey, bro, just wonderin’. grillbz couldn’t make it?”

“I DID ASK, AND INFORMED HIM OF THE NATURE OF THE PARTY.” Papyrus holds up his own sticky, melty bundle on a stick. “HE SEEMED OFFENDED.”

Sans watches his partner lean over to accept some marshmallows from the bag and give Asgore a kiss on the cheek as thanks. It elicits a giggle from the group, because Asgore clearly didn’t expect it. Sans chuckles along with them. His… partner. Yeah, they’re pretty great.

The worries he had clinging to him earlier over bringing them to meet everyone seem a world away.

That is, until the issue is pressed, loudly and in front of everyone.

“Hey, what's with these bullshit vague answers you've been feeding my best gal? How'd you actually meet? Was it super embarrassing? Was it one of those weirdly specific dating sites?”

Undyne reaches across two people just to punch Sans on the shoulder, so he's momentarily too busy cradling it and wondering what a dislocation is actually supposed to feel like -- surely he’d know for certain one way or another, so it's probably just pain -- to realize that the moment he's been dreading is actually upon him at last.

“Uh, we. We met at sch- uh, he’s- was my Physics 101 professor.”

All other conversations cease. Undyne, too, responds with uncanny quietness.

“Oh. I wasn’t serious, but isn't that kind of… fucked up?”

And there it is. He can't defend himself; anything he could say would be suspect, and anyway, he’s not even sure if he’s capable of defending himself. He’s entirely in their hands.

But he trusts them.

Maybe he shouldn't. They’re determined, they’re somewhere in the range of sneaky to downright devious when they want to be, they tend to act first and ask questions later, if ever, and it's all been in pursuit of him, which should tell him something about their judgement.

In spite of all this, he feels safe, sitting next to them as they squeeze his hand, as he hears about the last several months from their perspective for the first time. He watches the fire as he listens until a green negative image is burned into the back of his skull.

“Smitten, I guess you’d call it. Total cliché. I was the one making moves all the time, so any bad judgement, and, full disclosure, there was a lot of that, is on me, honest. I couldn’t stop thinking about him. So I figured I should make it clear he had me as an option, and…”

The roaring fire filling his vision is drastically warm, but he’s sweating cold.

“He was nothing short of upstanding about it. He put me off until the class was over, and I aced it. And he looked out for me the whole time. I almost gave up physics and now I’m pretty glad I didn’t. But he’s pushed for the right thing non-stop. I’m not his student any more. And hey, what’s age matter when you’re different species? I can’t change what I've done, and I wouldn't want to. I uh, I think I'll stick around, if he’ll have me.”

Sans has crumpled into himself like a bony orb. Surely they’re doing this just to embarrass him now. Everyone’s looking, and they grab him around the shoulders and plant a sloppy, wet smooch on his cheek. He groans. He doesn’t want everyone to see him blushing. Their hand feels for his neck and cups the back of his skull, which actually relaxes him a little.

A few of his friends are guffawing at his reaction, and he knows it’s because he doesn’t usually get like this. Undyne’s the only one who retains a grim sneer.

“Hmph. Well, whatever. They’re still way outta your league, buddy.”

His human adjusts him into a cuddle position and nuzzles the top of his head as the group’s attention drifts off. Alphys is trying to stop Monster Kid from sticking their head into the fire, marshmallows and stick gripped in their mouth.

“shit,” Sans mutters. “i think i really like you.”

“I think I like you too, pal,” they grin down at him and press a covert kiss to his cheek. Then his jaw. Then his nose. He jitters in place.

“uhh--”

“Nobody’s looking.”

With all his friends and acquaintances seated around them, no less. Just when he thinks he's about to combust from being too embarrassed and hot under the collar for other reasons, so close to an open flame, he feels them shudder as they extend another marshmallow towards the fire. For the first time, he notices they aren't really dressed properly for sitting out in the cold weather. Sure, the fire’s warm enough but they really are underdressed for the chill at their back.

“cold?” he asks to confirm.

“Nah, you're keeping me warm.”

He is doing no such thing, and he knows it, but he's almost willing to accept that answer at face value. After all, it's working on him. But then they shiver again, and their teeth begin to chatter.

Oof, he doesn't like that noise one bit.

“ugh. don't be like that. i'm gettin’ you a blanket. be right back.”

He slips away from the group and pops inside, grabbing a big, woolen blanket from the linen closet. It's scratchy, but it's warm, and anyway, it’s the only one he can physically reach. He returns as swiftly as he left; he doesn’t want to leave them cold for too long.

It's such a quick re-entry that he actually startles them when he settles the blanket around their shoulders.

“Holy hell, that was quick. Where’d you get this?”

“inside.”

“You sure you didn't just have this stuffed up in your chest cavity?”

He chuckles. He sits next to them again, and the blanket is big enough to wrap around their back, their front, and, he soon discovers not of his own volition, both his back and front as well.

They pinch it closed in the middle with their shoulders where they're leaning against each other, two misshapen wool pyramids with heads. But at least now, they’re warm misshapen wool pyramids with heads.

“Thanks. This is cozy.”

Roasting marshmallows isn't really an option like this, but it doesn't concern him. It's a good night and he feels foolish over his earlier concerns. He can relax and enjoy the company. It's safe to do so, it's all, all of it, safe.

Everyone is listening to Asgore tell a story about Undyne’s first piano lesson. Most everyone around the fire has already heard it several times over, but Sans’s attention is focused on one pair of eyes only, flicking from Asgore to Undyne and back again, rapt, and so expressive.

He almost has to laugh. So _this_ is what it looks like when they’re paying attention to someone without simultaneously undressing the object of that attention with their eyes. He'd almost forgotten.

He’s used to it, and yet the whole notion is simultaneously so alien. A couple of months isn’t nearly enough to fully absorb the idea of a human thinking about him that way.

Maybe it’s the fresh memory of those new kisses he’s savouring, like he was dying for them, maybe it’s the atmosphere with the firelight and having literally everyone he knows close by, maybe it’s watching the intent look on their face, simple and endearing. Without appearing to move at all from the outside of their blanket tent, he lets his hand drop onto their leg and squeezes.

He hears them take a little breath. There’s a smirk there. He did that.

The cuddling levels invisibly escalate from there. Sans has his ribs nudged-- stroked-- from top to bottom. He doesn’t even think about them flinching when his finger bones press into their skin, underneath their shirt. And when he tugs them in closer, as soon as no eyes are on them, his human leans over to sneak him a kiss.

Every time he gets one, he needs more. The reminder of having soft lips on him makes him wonder how he went minutes without it, let alone weeks.

He can’t say what he wants to, so he thinks loudly instead. Something along the lines of “kiss me” and “please” and “don’t stop”. He’s sweating more than ever now, and the toasty blanket feels almost too warm.

He watches them listen to Alphys going on a scientific rant, but he’s not paying attention. His beady eyes are fixed on their mouth and the lip-biting thing they do when they’re thinking _things_ about him.

He squirms in place, and like coming out of a daze he realises his cock is accidentally manifesting itself. He attempts to drive it down mentally. Which is exceptionally difficult when still trying to look normal in a crowd of people.

He can’t hold it back, it’s there. He’s huddled in a blanket with a goddamn hard-on. But as long as he and his human keep the covering up between them, nobody will know.

And because of that he keeps staring.

He wants them touching him again. Not under a blanket through his clothes, but bare and blatant just like the first time. He can remember it so well it’s going to doom him to unshakable arousal.

The fire begins to die down and the bags of marshmallows are finished off. In twos and threes, the party moves back indoors until none are left but the two of them and the crickets and the frogs.

They look back at the house, yellow light spilling out of the bottom floor windows.

“Hey, uh, not that it isn't terribly romantic to stare into a dying fire while I freeze to death, but is there a reason in particular we're still out here?”

“shit. sorry. uh, no, you go on inside, I'll catch up in a, uh… well, i'll catch up.”

They stand, but look at him askance, then back to the house.

“You sure? Nothing you want to talk about?”

“yeah, go. ‘s nothin’.”

Hands on hips, they frown at him from above, but appear to resign themselves for the time being.

“Yeah, ok. Have fun brooding, alone, in the dark.”

But before they go, a kiss. They bend down all the way at the hips, bracing themselves with a hand on his thigh, so, too close, at the exact moment their lips make contact with his jaw.

A long, low moan slips through the newly formed cracks in his composure.

“Uh,” they say, deadpan, but he can feel the muscles in their cheek bunch into a smile against his.

Without warning, they drop into a kneel in front of him, the pressure on his femur as they support more of their weight on him increasing until it compromises the structural integrity of the blanket. It drops from his shoulders and gaps just enough to divulge his state of arousal, unmitigated even after so many minutes of sitting and stewing.

They say nothing, eyes scanning from his face back down to his erection. He wants to cover himself. He also wants to break several public decency laws.

He ends up compromising by waiting for them to determine the course of events.

They brush a thumb across the very tip and he gasps, satisfied with his indecision. But he doesn't dare breathe, or move, lest he break whatever current is flowing through them both where they're connected and close. Either a log in the fire, or something inside of him, snaps when they press their lips against his jaw, nuzzling in the gap of his shirt collar. His hands seek them, to pull them in close, and he’ll never remember the desperate pleas and promises he’s rasping into their hair. 

They pull back from him, wide-eyed and slightly ravished, gulping in air. When they’ve had a moment, their mouth twists into a half grin. 

“Sans, this is… you don't play fair.”

“gnn, stay with me.”

They lose the grin, just like that.

“What?”

“tonight. or take me home with you.” When they don’t respond, he huffs. “stay over. so we can… uh, deal with this. i mean it.” He gently clears his throat. “...please.”

The dying crackles of the fire fill the silence.

“Uhhm…” The human’s eyes are still trained on him, entirely on the very area that wants their attention. “That’s… a pretty quick u-turn, there, big guy.”

That’s all they say.

Sans squirms as they keep staring. He definitely didn’t hear anything good, so he pulls the blanket closed and hunches over.

Their hand only slightly brushes and pats his shoulder, but he tenses up and grunts.

“I’ll wait for you inside. Maybe it’s better if I take off.”

All too soon he’s completely alone. He watches them disappear into the house and he hasn’t felt this worried in a long time. What did he just do that for? The sobering shock of being left behind is enough to dispense with his hard-on in record time. He keeps the blanket around his shoulders and trots inside, rubbing his brow, not knowing what to do. He’s never been cut out for this.

“BYE, UNDYNE! I’LL SEE YOU ON THURSDAY, RIGHT?”

He can hear Papyrus from the hallway, as groups of his friends start bundling up to leave. It is pretty late. He shuffles along to the door as well to receive a clap on the back and a wink from the fish warrior, and an acceptable, if not enthusiastic, fist bump from Alphys. Thankfully his regular grin is so practiced, there’s nothing to pick up on as he shoulders their praise.

Just as he's wondering if they've slipped out into the night without him noticing, without even a good night, Asgore's laugh echoes from the kitchen. Found ‘em.

He draws near but stays just out of sight, listening.

“God, yeah, I'd love to travel when I graduate, but I don't realistically see that happening. No, I think I'm just going to try to get a job,” they say.

Sans almost laughs. Leave it to Asgore to ask the one question every undergrad dreads.

“Why not?” he prods. “Something keeping you here?”

“Yeah, kinda,” they sigh.

Oh, hell.

_Oh, hell._

They don't think he would try to stop them, do they? They wouldn’t consider sticking around just for his sake if they wanted something else. They’re too smart for that, no, they must mean something else.

Worse, he wants them to stay. With him. He’d never ask it of them, he couldn't, but right in this moment he cannot bear the idea of waiting for them for half a semester only to lose them six months later. God, he’d been an idiot! Why did he tell them he wanted to wait? He might only have so much time anyway and now they’re convinced- and just now, they could've gone upstairs with no fuss and-

It is too damn soon to be worrying about this, what is _wrong_ with him? If they knew how badly just those few eavesdropped words shook him, they would surely run screaming into the night.

“Well, I'm sure you'll find a way of doing what you really want. You Determined ones always do, in the end.”

“Um, thanks? I think?”

Sans slips into the kitchen as Asgore leaves, catching the brunt of a hearty clap on the back right on his spine. He stiffens, mumbles a good night, and lifts the entire punch bowl to his mouth and drains it while the human watches in abject confusion.

“wasn't that much left,” he says.

The weatherproofing audibly sticks to the doorjamb as it closes, then leaves the house silent and still but for the muffled sounds of Papyrus goodbying from the driveway.

Sans puts the punch bowl in the sink and turns on the tap. The feeling of their gaze on his neck makes him sweat. The bowl fills and overflows with water.

“Sans?”

“mhm?”

“You're acting weird, are you ok?”

“nah, ‘m fine.”

“Are… are you seriously gonna sulk about this?”

He turns to face them at last. “‘bout what?”

“I mean, I'm sorry I left you out there, but I'm still pretty sure it was the right decision.” They sound less sure than they claim to be.

“oh. nah. ‘s fine.” He hadn't appreciated it, but they had at least had a point. Now, his main concern is trying not to scare them off. It's not working. He doesn’t look over and keeps quiet, hoping that not focusing on it with more conversation will make the moment pass. It doesn’t seem to, and now it feels like he’s sulking harder.

“If it’s not that, then I can’t just _guess_ what’s bothering you. I’m not a mind-reader.” If they were they definitely wouldn’t still have been hanging around with him. “And if it _is_ about earlier, I still say we’d better think about it, after we waited so long in the f--”

“yup, we did. how many more times are we gonna convince ourselves this is ‘doing it right’ because we’ve only been flirting for months and ignore that i’m your teacher?” Sans turns off the tap. He can’t bear to turn around.

“You’re not, not any more, we--”  
“i have this job. and i need it. i’m stuck here. you’re not stuck. you could go anywhere you want. do anything. be anyone. you’re only just getting started. ya don’t have to be that… the human that’s fuckin’ a skeleton….”

He hears them approach, slowly. “Sans, what? What is this? I didn’t… I figured I wasn’t a student to you any more.”

“you’re not. that’s the problem. i, fuck…”

He can’t get the mental image out of his head: his bright, eager, excited human, seeing the world, cycling down a desolate path in a European province, stopping to buy a weird, silly hat at a market, taking big, sure steps up a cliffside path, or a volcano. Things that, realistically, aren’t a picture he can fit into.

He turns to them, assuming that like always, he’d see their concern for him, something he’d started getting used to. Instead, he sees annoyance. His expectations for sympathy flutter and die. He’s a fucking moron.

“Please tell me what you’re getting at, because it sounds like a really dick move to overhear someone’s conversation and start making assumptions when you’ve never bothered to ask upfront.”

His human, laughing in the sun, on a boat across an endless ocean, dancing in decorative glowing bands from one club to the next, hiking to a lonely hilltop and spending hours looking at the stars.

His soul aches.

“what’s gonna happen?” he says, dismally. “what if it doesn’t… what if i’m not, uh…” roughness creeps into his voice. He swallows. They’re still looking at him, aloof and patient, waiting for him to finish a sentence. “if in a couple’a years, y’wake up next to this and realise it ain’t anythin’ you wanted?”

The heaviness in his tone is so damning. He’s loading all this onto them, suddenly, without the assurance of a friendly ear. He watches them like they’re in slow motion and he’s tracking every movement as if his life depends on it while his eye sockets sting with shame.

“Uh. Wow. Sans, d’you really wanna have, like, two years worth of fights all in one evening?”

He doesn’t reply. He can’t. Any movement, any action at all would fracture him and he’s on a knife-edge.

He waits it out and his pupils follow them as they go to get their coat. They put it on, tug at the collar, and level a steady gaze at him.

“This is all a bit much for me right now. Just… oh my god. We’ll talk later. I think we’re all pretty tired out.”

It happens so quickly - they’re gone. His head is swimming and he just barely hears their car pulling out of the driveway. He has enough willpower left to bid his brother a fond goodnight and then he shuts himself in his room. He curls up in the dark.


End file.
